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  • American Society of Hematology  (7,156)
  • American Geophysical Union  (6,179)
  • American Meteorological Society
  • 2005-2009  (15,303)
  • 1995-1999
  • 2008  (15,303)
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  • 2005-2009  (15,303)
  • 1995-1999
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  • 1
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    Volcanology and magma geochemistry of the present-day activity: constraints on the feeding system (2008)
    American Geophysical Union
    Details
    Publication Date: 2020-12-14
    Description: Stromboli volcano is famous in the scientific literature for its persistent state of activity, which began about 1500 years ago and consists of continuous degassing and mild intermittent explosions (normal Strombolian activity). Rare lava emissions and sporadic more violent explosive episodes (paroxysms) also occur. Since its formation, the present-day activity has been dominated by the emission of two basaltic magmas, differing chiefly in their crystal and volatile contents, whose characteristics have remained constant until now. The normal Strombolian activity and lava effusions are fed by a crystal-rich, degassed magma, stored within the uppermost part of the plumbing system, whereas highly vesicular, crystal-poor light-colored pumices are produced during paroxysms testifying to the ascent of volatile-rich magma batches from deeper portions of the magmatic system. Mineralogical, geochemical, and isotopic data, together with data on the volatile contents of magmas, are presented here with the aim of discussing (1) the relationships between the different magma batches erupted at Stromboli, (2) the mechanisms of their crystallization and transfer, (3) the plumbing system and triggering mechanisms of Strombolian eruptions.
    Description: Unpublished
    Description: 20
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: reserved
    Keywords: Stromboli volcano ; Basaltic explosive activity ; Basaltic pumice ; Plumbing system ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 2
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    Measurements of low amounts of precipitable water vapor by millimeter wave spectroscopy: An intercomparison with radiosonde, Raman lidar, and Fourier transform infrared data (2008)
    American Geophysical Union
    Details
    Publication Date: 2020-12-14
    Description: Observations of very low amounts of precipitable water vapor (PWV) by means of the Ground-Based Millimeter wave Spectrometer (GBMS) are discussed. Low amounts of column water vapor (between 0.5 and 4 mm) are typical of high mountain sites and polar regions, especially during winter, and are difficult to measure accurately because of the lack of sensitivity of conventional instruments to such low PWV contents. The technique used involves the measurement of atmospheric opacity in the range between 230 and 280 GHz with a spectral resolution of 4 GHz, followed by the conversion to precipitable water vapor using a linear relationship. We present the intercomparison of this data set with simultaneous PWV observations obtained with Vaisala RS92k radiosondes, a Raman lidar, and an IR Fourier transform spectrometer. These sets of measurements were carried out during the primary field campaign of the Earth Cooling by Water vapor Radiation (ECOWAR) project which took place at Breuil-Cervinia (45.9N, 7.6E, elevation 1990 m) and Plateau Rosa (45.9N, 7.7E, elevation 3490 m), Italy, from 3 to 16 March 2007. GBMS PWV measurements show a good agreement with the other three data sets exhibiting a mean difference between observations of 9%. The considerable number of data points available for the GBMS versus lidar PWV correlation allows an additional analysis which indicates negligible systematic differences between the two data sets.
    Description: Published
    Description: D14314
    Description: 1.8. Osservazioni di geofisica ambientale
    Description: JCR Journal
    Description: reserved
    Keywords: millimeter wave spectroscopy ; column water vapor ; 01. Atmosphere::01.01. Atmosphere::01.01.01. Composition and Structure
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
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    Recent extension driven by mantle upwelling beneath the Admiralty Mountains (East Antarctica) (2008)
    American Geophysical Union
    Details
    Publication Date: 2021-01-27
    Description: Northern Victoria Land is located at the boundary between an extended, presumably hot, region (West Antarctic Rift System) and the thick, possibly cold, East Antarctic craton. The style and timing of Tertiary deformation along with relationships with the magmatic activity are still unclear, and contrasting models have been proposed. We performed structural and morphotectonic analyses at the NE termination of northern Victoria Land in the Admiralty Mountains area, where the relationship between topography, tectonics, and magmatism is expected to be well pronounced. We found evidence of two subsequent episodes of faulting, occurring concurrently with the Neogene McMurdo volcanism. The first episode is associated with dextral transtension, and it is overprinted by extensional tectonics during the emplacement of large shield alkaline volcanoes. Upper mantle seismic tomography shows that the extensional regime is limited to regions overlying a low-velocity anomaly. We interpret this anomaly to be of thermal origin, and have tested the role of largescale upwelling on lithosphere deformation in the area. The results of this integrated analysis suggest that the morphotectonic setting of the region and the magmatism is likely the result of upwelling flow at the boundary between the cold cratonic and the hot stretched province (WARS), at work until recent time in this portion of the northern Victoria Land.
    Description: Published
    Description: TC4015
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: partially_open
    Keywords: Antarctica ; Admiralty Mountains ; Extensional Tectonics ; Mantle Upwelling ; Seismic Tomography ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 4
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    Investigation into magma degassing at Nyiragongo volcano, Democratic Republic of the Congo (2008)
    American Geophysical Union
    Details
    Publication Date: 2021-01-27
    Description: We report the first combined measurements of the composition and flux of gas emitted from Nyiragongo volcano by ground-based remote-sensing techniques. Ultraviolet spectroscopic measurements made in May/June 2005 and January 2006 indicate average SO2 emission rates of 38 kg s−1 and 23 kg s−1, respectively. Open-path Fourier transform infrared spectroscopic measurements obtained in May/June 2005, January 2006, and June 2007 indicate average molar proportions of 70, 24, 4.6, 0.87, 0.26, 0.11, and 0.0016% for H2O, CO2, SO2, CO, HCl, HF, and OCS, respectively. The composition of the plume was remarkably similar in 2005, 2006, and 2007, with little temporal variation in proportions of CO2, SO2, and CO, in particular, on the scale of seconds or days or even between the three field campaigns that span a period of 24 months. This stability persisted despite a wide range of degassing behaviors on the surface of the summit crater's lava lake (including discrete strombolian bursts and lava fountains) and variations in the SO2 emission rate. We explain these observations by a regime of steady state degassing in which bubbles nucleate and ascend in chemical equilibrium with the convecting magma. Short-term (seconds to minutes) temporal fluctuations in the SO2–HCl–HF composition were observed, and these are attributed to shallow degassing processes.
    Description: Published
    Description: Q02017
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Nyiragongo ; volcanic gas emissions ; FTIR ; DOAS ; remote sensing ; spectroscopy ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 5
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    Gulf Stream Variability in Five Oceanic General Circulation Models (2008)
    American Meteorological Society
    Details
    Publication Date: 2021-06-01
    Description: Five non-eddy-resolving oceanic general circulation models driven by atmospheric fluxes derived from the NCEP reanalysis are used to investigate the link between the Gulf Stream (GS) variability, the atmospheric circulation, and the Atlantic meridional overturning circulation (AMOC). Despite the limited model resolution, the temperature at the 200-m depth along the mean GS axis behaves similarly in most models to that observed, and it is also well correlated with the North Atlantic Oscillation (NAO), indicating that a northward (southward) GS shift lags a positive (negative) NAO phase by 0–2 yr. The northward shift is accompanied by an increase in the GS transport, and conversely the southward shift with a decrease in the GS transport. Two dominant time scales appear in the response of the GS transport to the NAO forcing: a fast time scale (less than 1 month) for the barotropic component, and a slower one (about 2 yr) for the baroclinic component. In addition, the two components are weakly coupled. The GS response seems broadly consistent with a linear adjustment to the changes in the wind stress curl, and evidence for baroclinic Rossby wave propagation is found in the southern part of the subtropical gyre. However, the GS shifts are also affected by basin-scale changes in the oceanic conditions, and they are well correlated in most models with the changes in the AMOC. A larger AMOC is found when the GS is stronger and displaced northward, and a higher correlation is found when the observed changes of the GS position are used in the comparison. The relation between the GS and the AMOC could be explained by the inherent coupling between the thermohaline and the wind-driven circulation, or by the NAO variability driving them on similar time scales in the models.
    Description: This research was supported by the PREDICATE project of the European Community, and for M. Bentsen by the Research Council of Norway through RegClim, NOClim, and the Programme of Supercomputing.
    Description: Published
    Description: 2119–2135
    Description: 3.7. Dinamica del clima e dell'oceano
    Description: JCR Journal
    Description: reserved
    Keywords: ocean modelling ; gulf stream variability ; 03. Hydrosphere::03.01. General::03.01.03. Global climate models
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 6
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    Seismic Tomography Experiment at Italy's Stromboli Volcano (2008)
    American Geophysical Union
    Details
    Publication Date: 2021-07-14
    Description: From 25 November to 2 December 2006, the first active seismic tomography experiment at Stromboli volcano was carried out with the cooperation of four Italian research institutions. Researchers on board the R/V Urania of the Italian National Council of Research (CNR), which was equipped with a battery of four 210- cubic- inch generated injection air guns (GI guns), fired more than 1500 offshore shots along profiles and rings around the volcano.
    Description: DPC/INGV agreement 2004-2006
    Description: Published
    Description: 269-270
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.6. Fisica del vulcanismo
    Description: N/A or not JCR
    Description: reserved
    Keywords: Stromboli ; seismic tomography ; air-gun ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 7
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    Earthquake-generated tsunamis in the Mediterranean Sea: scenarios of potential threats to Southern Italy (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: We calculated the impact on Southern Italy of a large set of tsunamis resulting from earthquakes generated by major fault zones of the Mediterranean Sea. Our approach merges updated knowledge on the regional tectonic setting and scenario-like calculations of expected tsunami impact. We selected three potential source zones located at short, intermediate and large distance from our target coastlines: the Southern Tyrrhenian thrust belt; the Tell-Atlas thrust belt; and the western Hellenic Arc. For each zone we determined a Maximum Credible Earthquake and described the geometry, kinematics and size of its associated Typical Fault. We then let the Typical Fault float along strike of its parent source zone and simulated all tsunamis it could trigger. Simulations are based on the solution of the nonlinear shallow water equations through a finite-difference technique. For each run we calculated the wave fields at desired simulation times and the maximum water elevation field, then produced travel-time maps and maximum wave-height profiles along the target coastlines. The results show a highly variable impact for tsunamis generated by the different source zones. For example, a large Hellenic Arc earthquake will produce a much higher tsunami wave (up to 5 m) than those of the other two source zones (up to 1.5 m). This implies that tsunami scenarios for Mediterranean Sea countries must necessarily be computed at the scale of the entire basin. Our work represents a pilot study for constructing a basin-wide tsunami scenario database to be used for tsunami hazard assessment and early warning.
    Description: Italian Civil Defense; Project “Development of new technologies for the protection of the Italian territory from natural hazards” funded by the Italian Ministry of University and Research
    Description: Published
    Description: B01301
    Description: 3.1. Fisica dei terremoti
    Description: 3.2. Tettonica attiva
    Description: 4.2. TTC - Scenari e mappe di pericolosità sismica
    Description: JCR Journal
    Description: partially_open
    Keywords: Tsunamis ; Mediterranean Sea ; Seismotectonics ; 03. Hydrosphere::03.01. General::03.01.01. Analytical and numerical modeling ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 8
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    Using Temperature–Salinity Relations in a Global Ocean Implementation of a Multivariate Data Assimilation Scheme (2008)
    American Meteorological Society
    Details
    Publication Date: 2017-04-04
    Description: In this paper results from the application of an ocean data assimilation (ODA) system, combining a multivariate reduced-order optimal interpolator (OI) scheme with a global ocean general circulation model (OGCM), are described. The present ODA system, designed to assimilate in situ temperature and salinity observations, has been used to produce ocean reanalyses for the 1962–2001 period. The impact of assimilating observed hydrographic data on the ocean mean state and temporal variability is evaluated. A special focus of this work is on the ODA system skill in reproducing a realistic ocean salinity state. Results from a hierarchy of different salinity reanalyses, using varying combinations of assimilated data and background error covariance structures, are described. The impact of the space and time resolution of the background error covariance parameterization on salinity is addressed.
    Description: This work has been funded by the ENACT Project (Contract EVK2-CT2001-00117) for A. Bellucci and P. Di Pietro, and partially by the ENSEMBLES Project (Contract GOCE-CT-2003-505539) for A. Bellucci.
    Description: Published
    Description: 3785-3807
    Description: 3.7. Dinamica del clima e dell'oceano
    Description: JCR Journal
    Description: reserved
    Keywords: ocean modelling ; data assimilation ; reanalysis ; upper ocean variability ; temperature ; Salinity ; 03. Hydrosphere::03.01. General::03.01.04. Ocean data assimilation and reanalysis
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 9
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    The changing face of Mount Etna’s summit area documented with Lidar technology (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: Morphostructural data derived from Lidar (Light detection and ranging) surveys carried out on Mount Etna in 2005 and 2007 are compared with earlier aerophotogrammetric surveys in 1986 and 1998. These data render an unprecedentedly clear and quantitative image of morphostructural and volumetric changes that have affected the summit area of the volcano in the past two decades and permit the production of a new topographic map. The computed volume gain during the 1986–2007 period amounts to 112 ± 12 106 m3, at a mean annual rate of 5.3 106 m3. The comparison of the various surveys furthermore emphasizes the levels of accuracy and resolution of the different techniques applied. The Lidar technology used in 2007 allows production of high-precision maps in near-real-time, facilitating work concerning environmental hazards such as numerical simulations of, e.g., lava flows.
    Description: Published
    Description: L09305
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 1.10. TTC - Telerilevamento
    Description: JCR Journal
    Description: partially_open
    Keywords: Lidar ; Etna ; morphostructural changes ; lava flows ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
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    Continuous monitoring of soil CO2 flux on Mt. Etna:The 2004–2005 eruption and the role of regional tectonics and volcano tectonics. (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: The soil CO2 flux on Mt. Etna as recorded by the ETNAGAS network (an automatic system for measuring soil CO2 flux and meteorological parameters) started to increase strongly about 5 months prior to the onset of the 2004–2005 eruption and decreased a few months before the end of the eruption. Time delays in the occurrences of anomalies in soil CO2 flux at different sites in the geochemical network constrain the relationship between soil CO2 flux distributions and the tectonic framework of Etna volcano. The anomalies observed before the 2004–2005 eruption support the intrusion of new undegassed magma into the upper feeding system of the volcano (〈20 km below sea level). Magma subsequently rose slowly in the volcano conduits, thereby triggering the onset of the 2004–2005 eruption. The time delays in the occurrences of anomalies in combination with spectral analysis indicate the importance of tectonic and volcanotectonic structures in driving the ascent of deep gases within the crust. Moreover, greatest amplitude pulsations of the low-frequency components of the CO2 flux signals were correlated with the paroxystic activities of the 2004–2005 eruption. This study confirms that CO2 flux variation is a useful indicator for volcanic activity in the surveillance of the Mt. Etna and similar basaltic volcanoes.
    Description: Dipartimento Protezione Civile Ministero degli Interni
    Description: Published
    Description: B09206
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: reserved
    Keywords: CO2 flux ; Continuous monitoring of soil CO2 flux ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 11
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    Deep-sea deposits of the 30 december 2002 landslide (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: Stromboli is a 3000-m-high, conical island-arc volcano rising to 900 m above sea level. It is the most active volcano of the Aeolian Archipelago in the Tyrrhenian Sea (Italy). In the last 13 Kr four large-volume (1 km3) flank collapses have played an important role in shaping the northwestern flank (Sciara del Fuoco- SdF) of the volcano. These flank collapses have the potential to cause hazardous tsunamis in the Aeolian islands and farther afield along the Italian coast. In addition, smaller volume, much more frequent partial collapses of the SdF have been shown to be tsunami generating, potentially hazardous events One such partial collapse occurred on 30/12/2002, on the north-western flank of the island. The resulting landslide generated a 10-m-high tsunami that impacted the island. Multibeam bathymetry, side-scan sonar and seabed visual observations reveal that 25-30 x 106 m3 of sediments were deposited on the offshore from the Sciara del Fuoco landslide. Sediment samples have led to the recognition of a proximal coarse-grained landslide deposit on the volcano slope and a distal, cogenetic, sandy turbidite 24 km from the Stromboli shoreline. The proximal landslide deposit consists of two contiguous facies: (1) a chaotic, coarse grained (meter- to centimetre-sized clasts) deposit and (2) a sand deposit containing a lower, cross bedded sand layer and an upper structureless, pebbly sand bed, capped by seafloor ripple bedforms. The ubiquitous sand facies develops laterally with and over the coarse-grained deposits. Distally, a capping 2-3 cm-thick sand layer, not present in a pre-landslide September 2002 core, is interpreted as the finer grained turbidite equivalent of the proximal deposits. Characteristics of the SdF landslide deposits suggest that they derive from cohesionless, sandy-matrix, density flows. Flow rheology resulted in segregation of the density flow into sand-rich and clast-rich regions. Our results show that a range of density flow transitions, based principally on particle concentration and grain-size partitioning of cohesionless parent flows, can be identified in the proximal and distaldeposits of this relatively small-scale landslide event on Stromboli.
    Description: Unpublished
    Description: 23
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: open
    Keywords: Stromboli ; flank collapse ; tsunami ; submarine landslide deposits ; 04. Solid Earth::04.04. Geology::04.04.04. Marine geology ; 04. Solid Earth::04.04. Geology::04.04.08. Sediments: dating, processes, transport ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 12
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    Stress interaction effect on the occurrence probability of characteristic earthquakes in Central Apennines (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: In this study, we compute the effect of stress change due to previous historical earthquakes on the probability of occurrence of future earthquakes on neighboring faults. Following a methodology developed in the last decade, we start from the estimate of the probability of occurrence in the next 50 years for a characteristic earthquake on known seismogenic structures, based on a time-dependent renewal model. Then a physical model for the Coulomb stress change caused by previous earthquakes on these structures is applied. The influence of this stress change on the occurrence rate of characteristic earthquakes is computed, taking into account both permanent (clock advance) and temporary (rate-and-state) perturbations. We apply this method to the computation of earthquake hazard of the main seismogenic structures recognized in the Central and Southern Apennines region, for which both historical and paleoseismological data are available. This study provides the opportunity of reviewing the problems connected with the estimate of the parameters of a renewal model in case of characteristic earthquakes characterized by return times longer than the time spanned by the available catalogues and the applicability of the concept of characteristic earthquake itself. The results show that the estimated effect of earthquake interaction in this region is small compared with the uncertainties affecting the statistical model used for the basic time-dependent hazard assessment.
    Description: Published
    Description: B08313
    Description: 3.1. Fisica dei terremoti
    Description: 3.2. Tettonica attiva
    Description: 4.2. TTC - Scenari e mappe di pericolosità sismica
    Description: JCR Journal
    Description: reserved
    Keywords: Stress interaction, occurrence probability, characteristic earthquakes ; 01. Atmosphere::01.02. Ionosphere::01.02.03. Forecasts ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.06. Seismology::04.06.02. Earthquake interactions and probability ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
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  • 13
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    Atmospheric horizontal resolution affects tropical climate variability in coupled models (2008)
    American Meteorological Society
    Details
    Publication Date: 2017-04-04
    Description: The effect of horizontal resolution on tropical variability is investigated within the modified SINTEX model, SINTEX-F, developed jointly at INGV, IPSL and at the Frontier Research System. The horizontal resolutions T30 and T106 are investigated in terms of the coupling characteristics, frequency and variability of the tropical ocean-atmosphere interactions. It appears that the T106 resolution is generally beneficial even if it does not eliminate all the major systematic errors of the coupled model. There is an excessive shift west of the cold tongue and ENSO variability, and high resolution has also a somewhat negative impact to the variability in the East Indian Ocean. A dominant two-year peak for the NINO3 variabilty in the T30 model is moderated in the T106 as it shifts to longer time scale. At high resolution new processes come into play, as the coupling of tropical instability waves, the resolution of coastal flows at the Pacific Mexican coasts and improved coastal forcing along the coast of South America. The delayed oscillator seems the main mechanism that generates the interannual variability in both models, but the models realize it in different ways. In the T30 model it is confined close to the equator, involving relatively fast equatorial and near-equatorial modes, in the high resolution, it involves a wider latitudinal region and slower waves. It is speculated that the extent of the region that is involved in the interannual variability may be linked to the time scale of the variability itself.
    Description: This research was partially supported by the Italy–USA Cooperation Program of the Italian Ministry of Environment and by the EU projects ENSEMBLES and DYNAMITE.
    Description: Published
    Description: 730-750
    Description: 3.7. Dinamica del clima e dell'oceano
    Description: JCR Journal
    Description: reserved
    Keywords: coupled models ; tropical variability ; ENSO system ; 03. Hydrosphere::03.01. General::03.01.03. Global climate models
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 14
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    Rupture process of the 2007 Niigata-ken Chuetsu-oki earthquake by non-linear joint inversion of strong motion and GPS data (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: We image the rupture history of the 2007 Niigata-ken Chuestu-oki (Japan) earthquake by a nonlinear joint inversion of strong motion and GPS data, retrieving peak slip velocity, rupture time, rise time and slip direction. The inferred rupture model contains two asperities; a small patch near the nucleation and a larger one located 10÷15 km to the south-west. The maximum slip ranges between 2.0 and 2.5 m and the total seismic moment is 1.6×1019 Nm. The inferred rupture history is characterized by rupture acceleration and directivity effects, which are stable features of the inverted models. These features as well as the source-to-receiver geometry are discussed to interpret the high peak ground motions observed (PGA is 1200 gals) at the Kashiwazaki-Kariwa nuclear power plant (KKNPP), situated on the hanging-wall of the causative fault. Despite the evident source effects, predicted PGV underestimates the observed values at KKNPP by nearly a factor of 10.
    Description: Published
    Description: L16306
    Description: 3.1. Fisica dei terremoti
    Description: JCR Journal
    Description: partially_open
    Keywords: rupture process ; inversion ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
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  • 15
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    Scientific community and civil protection synergy during the Stromboli 2002-03 eruption (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: The eruption of Stromboli 2002-03, thanks to its complex scenario (flank instability, tsunami, necessity to rapidly upgrade monitoring networks) has provided an important opportunity to verify the response of the national system of civil protection to volcanic emergencies. In particular, it has tested and validated the model of collaboration, in use by Italian law, between the Department of Civil Protection and the National Institute of Geophysics and Volcanology. This synergy has enabled a better understanding and ability to tackle the eruptive crisis from its first stages, as well as implement monitoring systems both dependably and swiftly. In this work, the numerous first monitoring tasks carried out during the critical initial stages of the eruption are described, and the activities and planned action are reported over the course of the eruption that has made Stromboli one of the best monitored volcanoes not only in Italy but throughout the world.
    Description: Published
    Description: 387-398
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: open
    Keywords: eruptive crisis management ; Stromboli volcano ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 16
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    Gas Flux Rate and Migration of the Magma Column (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: The 2002–2003 effusive eruption of Stromboli volcano represents an excellent opportunity to investigate the transition from effusive to explosive activity at an open-conduit basaltic system, when activity migrated from effusive vents, at the base of the craters, to summit explosions. The transition is investigated here through the analysis of very long period seismicity, delay times between infrasonic and thermal onsets of explosions, and SO2 flux recorded during a 1-year period. The synergy of the multiple geophysical observations points to a magma-driven migration of the magma column. Here the increased magma supply at the eruption onset lead to opening of effusive fissures, which draining the magma in the shallow conduit caused the decrease of the magma level. The decrease of the magma supply at the end of the effusion lead to sealing of effusive fissures, upraise of the magma level within the conduit, and reestablishment of explosive activity from the summit vents.
    Description: Unpublished
    Description: 11
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 1.10. TTC - Telerilevamento
    Description: 3.6. Fisica del vulcanismo
    Description: reserved
    Keywords: Stromboli ; SO2 Flux ; Magma column ; Infrasound ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 17
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    Validation of the Aura Microwave Limb Sounder HNO3 Measurements (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-03
    Description: We assess the quality of the version 2.2 (v2.2) HNO3 measurements from the Microwave Limb Sounder (MLS) on the Earth Observing System Aura satellite. The MLS HNO3 product has been greatly improved over that in the previous version (v1.5), with smoother profiles, much more realistic behavior at the lowest retrieval levels, and correction of a high bias caused by an error in one of the spectroscopy files used in v1.5 processing. The v2.2 HNO3 data are scientifically useful over the range 215 to 3.2 hPa, with single-profile precision of 0.7 ppbv throughout. Vertical resolution is 3–4 km in the upper troposphere and lower stratosphere, degrading to 5 km in the middle and upper stratosphere. The impact of various sources of systematic uncertainty has been quantified through a comprehensive set of retrieval simulations. In aggregate, systematic uncertainties are estimated to induce in the v2.2 HNO3 measurements biases that vary with altitude between ±0.5 and ±2 ppbv and multiplicative errors of ±5–15% throughout the stratosphere, rising to ±30% at 215 hPa. Consistent with this uncertainty analysis, comparisons with correlative data sets show that relative to HNO3 measurements from ground-based, balloon-borne, and satellite instruments operating in both the infrared and microwave regions of the spectrum, MLS v2.2 HNO3 mixing ratios are uniformly low by 10–30% throughout most of the stratosphere. Comparisons with in situ measurements made from the DC-8 and WB-57 aircraft in the upper troposphere and lowermost stratosphere indicate that the MLS HNO3 values are low in this region as well, but are useful for scientific studies (with appropriate averaging).
    Description: Published
    Description: D24S40
    Description: 1.7. Osservazioni di alta e media atmosfera
    Description: JCR Journal
    Description: reserved
    Keywords: satellite validation ; stratospheric HNO3 ; 01. Atmosphere::01.01. Atmosphere::01.01.01. Composition and Structure
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  • 18
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    Sliding episodes during the 2002–2003 Stromboli lava effusion: Insights from seismic, volcanic, and statistical data analysis (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: Repeated phenomena of flank instability accompanied the 28 December 2002 to 21 July 2003 eruption of Stromboli volcano. The major episodes were two tsunamigenic landslides on 30 December 2002, 2 d after the volcano unrest. After 30 December, sliding processes remodeled the area affected by slope instability.We propose analyses of 565 sliding episodes taking place from December 2002 to February 2003.We try to shed light on their main seismic features and links with the ongoing seismic and volcanic activity using variogram analysis as well. A characterization of the seismic signals in the time and frequency domains is presented for 185 sliding episodes. Their frequency content is between 1 Hz and 7 Hz. On the basis of the dominant peaks and shape of the spectrum, we identify three subclasses of signals, one of which has significant energy below 2 Hz. Low-frequency signatures were also found in the seismic records of the landslides of 30 December, which affected the aerial and submarine northwestern flank of the volcano. Accordingly, we surmise that spectral analysis might provide evidence of sliding phenomena with submarine runouts.We find no evidence of sliding processes induced by earthquakes. Additionally, a negative statistical correlation between sliding episodes and explosion quakes is highlighted by variogram analysis. Variograms indicate a persistent behavior, memory, of the flank instability from 5 to 10 d.We interpret the climax in the occurrence rate of the sliding processes between 24 and 29 January 2003 as the result of favorable conditions to slope instability due to the emplacement of NW-SE aligned, dike-fed vents located near the scarp of the landslide area. Afterward, the stabilizing effect of the lava flows over the northwestern flank of the volcano limited erosive phenomena to the unstable, loose slope not covered by lava.
    Description: This work was supported financially by Istituto Nazionale di Geofisica e Vulcanologia and Dipartimento per la Protezione Civile, project INGV-DPC V4/02.
    Description: Published
    Description: Q04022
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: rockfalls ; seismicity ; volcanoes ; volcano collapses ; Stromboli ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 19
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    Modeling seismicity rate changes during the 1997 Umbria-Marche sequence (central Italy) through a rate- and state-dependent model (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: We model the spatial and temporal pattern of seismicity during a sequence of moderate-magnitude normal faulting earthquakes, which struck in 1997 the Umbria-Marche sector of Northern Apennines (Italy), by applying the Dieterich (1994) rate- and state-dependent constitutive approach. The goal is to investigate the rate of earthquake production caused by repeated coseismic stress changes computed through a 3-D elastic dislocation model in a homogeneous half-space. The reference seismicity rate is assumed time independent, and it is estimated by smoothing the seismicity that occurred in the previous decade without declustering. We propose an analytical relation for deriving the stressing rate directly from the reference seismicity rate. This allows us to perform a tuning of the constitutive parameter As (where A accounts for the direct effect of friction in the rate- and state-dependent model and s is the effective normal stress) into the Dieterich model through a maximum likelihood method, which yields for this seismic sequence a best fitting value equal to 0.04 MPa. Our computations show that, although seven out of eight main shocks are located in areas of increased rate of earthquake production, numerous aftershocks are located in seismicity shadows. Our simulations point out that the adopted value of As strongly affects the pattern of both seismicity shadow and areas of enhanced rate of earthquake production. We conclude that solely accounting for static stress changes caused by the main shocks of this seismic sequence is not sufficient to forecast the complex spatial and temporal evolution of seismicity.
    Description: Published
    Description: B11301
    Description: 3.1. Fisica dei terremoti
    Description: JCR Journal
    Description: reserved
    Keywords: rate-and-state ; Umbria-Marche 1997-98 ; 04. Solid Earth::04.06. Seismology::04.06.02. Earthquake interactions and probability
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  • 20
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    Strong evidence for non-similar earthquake source scaling in central Italy (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: scaling of seismic sources of the Central Apennines (Italy) is investigated using broadband seismograms from the Colfiorito sequence (4〈=Mw〈=6 ). Our results are not consistent with self-similar scaling, and can be described by the following relationship: M0~fc^-(3_epsilon), where epsilon=1.7+-0.3 . We speculate that dynamic fault lubrication by fluid pressurization may be responsible for such extreme behavior, and use our results for the calibration of a weak-motion-based predictive relationship for the ground motion ( Mw〈=4.1) up to Mw~6 for this region.
    Description: Published
    Description: L17303
    Description: 3.1. Fisica dei terremoti
    Description: JCR Journal
    Description: reserved
    Keywords: Self-similarity ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
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  • 21
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    Variation of H2O/CO2 and CO2/SO2 ratios of volcanic gases discharged by continuous degassing of Mount Etna volcano, Italy (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: We applied the Multi-GAS technique to measure compositions of the volcanic plumes continuously discharged from summit craters of Voragine, Northeast and Bocca Nuova at Mount Etna, in an attempt to estimate compositions of the source volcanic gases. The estimated CO2/SO2 and H2O/CO2 ratios of the volcanic gases show a large variation ranging from 0.6 to 30 and from 1 to 18, respectively. This variability overlaps with the compositional range of dissolved volatiles in melt inclusions and their coexisting bubbles in a magma chamber and can be caused by the low-pressure degassing of a magma with variable bubble content ranging from 0.3 to 15 wt.%. The variable bubble content in the magma is likely a result of supply of deep-derived CO2-rich gas phase to the chamber and subsequent bubble-magma differentiation by bubble ascent in the magma chamber. In contrast, the variation of volcanic gas composition can also be caused by changes of degassing pressure (gas–magma separation pressure), ranging from 0 to 100 MPa, as a result of changes in the depth of the top of the convecting magma in volcanic conduits. Both mechanisms can cause similar compositional variations. However, the two mechanisms will result in contrasting correlations between the SO2 emission rates and the gas compositions that can be examined by parallel observations of the emission rates and compositions in the future.
    Description: Published
    Description: B09203
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 4.5. Degassamento naturale
    Description: JCR Journal
    Description: reserved
    Keywords: Plume ; gas ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 22
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    Static stress changes induced by the magmatic intrusions during the 2002–2003 Etna eruption (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: The shallow intrusive processes that occurred during 2002–2003 Etna eruption, as well as the complex interaction between the magma intrusive events and the tectonic response of the volcano’s eastern flank, are investigated with numerical deformation modeling and the estimation of changes in the static Coulomb stress. Ground deformation and volcanologic evidence clearly indicate a composite mechanism of intrusion on both the southern and northeastern flanks of the volcano. Geodetic data inversions have been based on a homogeneous elastic half-space model, although geological data and seismic tomography indicate that Mt. Etna is elastically inhomogeneous and that rigidity layering and heterogeneities are likely to affect the magnitude and pattern of the deformation field. To account for topographic effects, as well as a complicated distribution of material properties, we use the finite element method (FEM) to provide a more realistic model. The presence of medium heterogeneity strongly affects the amplitudes of the static stress changes. Seismicity matches well the areas of positive increase in the static stress caused by the intrusive events along the southern and northeastern flanks. The changes in the state of stress generated by the southern dike produce an extensional stress field that favors magma propagation along the north-east Rift. The highest seismic releases were associated with the activation of two fault systems, the Timpe Fault System and the Pernicana Fault. The static stress changes resolved onto these faults indicate that the magma intrusions on the southern and northeastern flanks encouraged these seismogenic structures to slip.
    Description: Published
    Description: B10206
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: numerical modeling ; ground defromation ; static stress changes ; volcano activity ; 04. Solid Earth::04.03. Geodesy::04.03.08. Theory and Models
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 23
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    Unmanned aerial vehicle measurements of volcanic carbon dioxide fluxes (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: We report the first measurements of volcanic gases with an unmanned aerial vehicle (UAV). The data were collected at La Fossa crater, Vulcano, Italy, during April 2007, with a helicopter UAV of 3 kg payload, carrying an ultraviolet spectrometer for remotely sensing the SO2 flux (8.5 Mg d 1), and an infrared spectrometer, and electrochemical sensor assembly for measuring the plume CO2/SO2 ratio; by multiplying these data we compute a CO2 flux of 170 Mg d 1. Given the deeper exsolution of carbon dioxide from magma, and its lower solubility in hydro-thermal systems, relative to SO2, the ability to remotely measure CO2 fluxes is significant, with promise to provide more profound geochemical insights, and earlier eruption forecasts, than possible with SO2 fluxes alone: the most ubiquitous current source of remotely sensed volcanic gas data.
    Description: Published
    Description: L06303
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Plume measurements ; carbon dioxide fluxes ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 24
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    Source process of the September 12, 2007 MW 8.4 Southern Sumatra earthquake from tsunami tide gauge record inversion (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: We infer the slip distribution and average rupture velocity of the magnitude MW 8.4 September 12, 2007, southern Sumatra earthquake from available tide-gauge records of the ensuing tsunami. We select 9 waveforms recorded along the west coast of Sumatra and in the Indian Ocean. Slip distribution and rupture velocity are determined simultaneously by means of a non linear inversion method. We find high slip values (∼10 m) into a patch 100 km long and 50 km large, between 20 and 30 km of depth, about 100 km north-west from the epicenter. We conclude this earthquake did not rupture the whole area of the 1833 event, indicating some slip has still to occurr. Our estimate of rupture velocity is of 2.1±0.4 km/sec. The relatively large depth of the main slip patch is the likely explanation for the low damaging observed tsunami.
    Description: Published
    Description: L02310
    Description: 3.1. Fisica dei terremoti
    Description: JCR Journal
    Description: partially_open
    Keywords: Sumatra ; tsunami ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
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  • 25
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    2002–2003 Lava Flow Eruption of Stromboli: A Contribution to Understanding Lava Discharge Mechanisms Using Periodic Digital Photogrammetry Surveys (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: Photogrammetric surveys were performed between 5 January and 26 July 2003 for monitoring the NW flank of the Sciara del Fuoco (SdF) during the eruption of Stromboli that started on 28 December 2002. The collected data were used both for controlling morphological changes after the major landslide that occurred on 30 December 2002 and lava flow field evolution until the end of the eruption (22 July 2003). The latter objective was achieved by a quantitative analysis which allowed to estimate the total lava volume (12.51 × 106 m3) emplaced on the SdF slope corresponding to an eruption rate of about 0.69 m3/s. Thanks to the availability of multitemporal data set, which made this event the first well-documented and regularly surveyed Stromboli eruption, the cumulative volume and effusion rate trends were derived. A model for interpreting the behavior of the 2002–2003 Stromboli effusive eruption is also proposed: being the vents located very close to the volcano summit, a typical summit (terminal) basaltic lava flow eruption was expected; on the contrary, the observed effusion rate trend showed an initial peak followed by an exponential decline typical of flank (lateral) eruptions of basaltic volcanoes. We recognized in this trend a transition from a terminal (open conduit system) to a lateral (pressurized dike system) lava discharge followed by a longer period in which the elastic strain energy from the subvolcanic reservoir controlled the effusion rate; this effect counterbalanced the lava cooling at dike tip that tends to close the eruptive fissure causing the eruption end.
    Description: Published
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: reserved
    Keywords: Stromboli ; Digital photogrammetry survey ; lava disharge mechanism ; morphological changes ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 26
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    CO2/CH4 ratio in fumaroles a powerful tool to detect magma degassing episodes at quiescent volcanoes (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: Long time series of fumarolic compositions at Campi Flegrei (Italy), Mammoth Mountain (California), Panarea (Italy) and Nisyros (Greece) show rapid increases, up to orders of magnitude, of the CO2/CH4 ratio systematically with the occurrence of volcanic unrest periods. These easily detected anomalies originate with the arrival of CH4-poor magmatic fluids in the shallower levels of the volcanoes. The data suggest that volcanoes are characterized by magmatic activity at depth also in periods of apparent quiescence. The activity is constituted by the pulsing release of large amount of fluids which either cause unrest periods (seismicity and ground deformation) or possibly could precede volcanic eruption. This type of volcanic activity can be monitored trough the classical geophysical techniques together with the systematic sampling and analysis of fumaroles.
    Description: In press
    Description: 4.5. Degassamento naturale
    Description: JCR Journal
    Description: reserved
    Keywords: fumarole ; magma degassing ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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  • 27
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    A bayesian approach to the real time estimation of magnitude from the early P- and S-wave displacement peaks (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: It has been shown that the initial portion of P and S wave signals can provide information about the final earthquake magnitude in a wide magnitude range. This observation opens the perspective for the real-time determination of source parameters. In this paper we describe a probabilistic evolutionary approach for the real-time magnitude estimation which can have a potential use in earthquake early warning. The technique is based on empirical prediction laws correlating the low-frequency peak ground displacement measured in a few seconds after the P and/or S phase arrival and the final event magnitude. The evidence for such a correlation has been found through the analysis of 256 shallow crustal events in the magnitude range Mjma 4–7.1 located over the entire Japanese archipelago. The peak displacement measured in a 2-s window from the first P phase arrival correlates with magnitude in the range M = [4–6.5]. While a possible saturation effect above M ’ 6.5 is observed, it is less evident in an enlarged window of 4 s. The scaling of S peaks with magnitude is instead also observed at smaller time lapses (i.e., 1 s) after the first S arrival. The different scaling of P and S peaks with magnitude when measured in a 2-s window is explained in terms of different imaged rupture surface by the early portion of the body wave signals. We developed a technique to estimate the probability density function (PDF) of magnitude, at each time step after the event origin. The predicted magnitude value corresponds to the maximum of PDF, while its uncertainty is given by the 95% confidence bound. The method has been applied to the 2007 (Mjma = 6.9) Noto Hanto and 1995 (Mjma = 7.3) Kobe earthquakes. The results of this study can be summarized as follows: (1) The probabilistic algorithm founded on the predictive model of peak displacement versus final magnitude is able to provide a fast and robust estimation of the final magnitude. (2) The information available after a few seconds from the first detection of the P phase at the network can be used to predict the peak ground motion at a given regional target with uncertainties which are comparable to those derived from the attenuation law. (3) The near-source S phase data can be used jointly with P data for regional early warning purposes, thus increasing the accuracy and reliability of magnitude estimation.
    Description: Published
    Description: B12302
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: JCR Journal
    Description: reserved
    Keywords: Bayesian approach ; P and S wave ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution
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  • 28
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    Link between major flank slip and 2002–2003 eruption at Mt. Etna (Italy) (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: The 2002–2003 Etna eruption is studied through earthquake distributions and surface fracturing. In September 2002, earthquake-induced surface rupture (sinistral offset 0.48 m) occurred along the E-W striking Pernicana Fault (PF), on the NE flank. In late October, a flank eruption accompanied further ( 0.77 m) surface rupturing, reaching a total sinistral offset of 1.25 m; the deformation then propagated for 18 km eastwards to the coastline (sinistral offset 0.03 m) and southwards, along the NW-SE striking Timpe (dextral offset 0.04 m) and, later, Trecastagni faults (dextral offset 0.035 m). Seismicity (〈4 km bsl) on the E flank accompanied surface fracturing: fault plane solutions indicate an overall ESEWNWextension direction, consistent with ESE slip of the E flank also revealed by ground fractures. A three-stage model of flank slip is proposed: inception (September earthquake), climax (accelerated slip and eruption) and propagation (E and S migration of the deformation).
    Description: Published
    Description: 2286
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.2. Tettonica attiva
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: volcano seismology ; surface fracturing ; flank slip ; eruption ; Etna ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.02. Earthquake interactions and probability ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 29
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    Crustal structure at colliding plates boundary from receiver functions analysis: A close look beneath the northern Apennines (Italy) (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: Teleseismic receiver functions from a seismic experiment in a small area of the northern Apennines, Italy, reveal strong crustal structure variations across the mountain chain. Receiver functions imaging and full waveform inversion technique are used to constrain the S-wave velocity profile in the crust and to reconstruct the geometry of the main seismic discontinuities at depth. We highlight the presence of the main mode-converting discontinuities in the study area. Most importantly, we identify the crust-mantle transition which is represented, almost everywhere in the study area, by a sharp S-wave velocity increase (over 4 km/s) at depth between 35 and 40 km. However, farther west, the S-wave velocity reaches values typical for the sub-crustal mantle at about 54 km depth, possibly marking the locus where the subducting Adriatic plate starts to dip into the mantle. Here the presence of a shallower discontinuity at about 36 km depth, with S-velocity values around 4 km/s, can be interpreted as the Moho signature of the overriding Tyrrhenian plate.
    Description: Published
    Description: L12304
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: receiver functions ; northern Apennines ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
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  • 30
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    Volcanomagnetic Evidence of the Magmatic Intrusion on 13th May 2008 (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: During the onset of 2008 volcanic crisis at Mt Etna, the near-real time magnetic data provided a continuous updating of the volcano activity state on the northern flank. On the morning of 13th May 2008, significant local magnetic field changes marked the resumption of the eruptive activity characterized by the opening of a fracture field on the northern flank, and an eruptive fissure in the Valle del Bove. In agreement with the northward propagation of seismic events, magnetic signals at 5 stations in the summit area revealed a nearly NNW-SSE oriented magmatic intrusion, which started at about 9:00 GMT, propagated northward for about 2 km, and stopped at 14:00 GMT before reaching the North-East Rift. Magnetic variations, with amplitude ranging between 1.8 nT and -6.5 nT, are consistent with those calculated from piezomagnetic models, where stress-induced changes in rock magnetization are produced by the magmatic intrusion.
    Description: Published
    Description: L22301
    Description: 2.6. TTC - Laboratorio di gravimetria, magnetismo ed elettromagnetismo in aree attive
    Description: JCR Journal
    Description: partially_open
    Keywords: Mt Etna ; volcano monitoring ; piezomagnetic field ; magmatic intrusion ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 31
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    Gravity “steps” at Mt. Etna volcano (Italy). Instrumental effects or evidences of earthquake-triggered magma density changes? (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: On two occasions, sudden gravity changes occurred simultaneously at two summit Etna’s stations, during local low-magnitude earthquakes. A systematic coupling between earthquakes inducing comparable maximum acceleration and displacement at the observation points and gravity steps is missing, implying (a) the non-instrumental nature of the steps and (b) the need for particular underlying conditions for the triggering mechanism(s) to activate. We review some of the volcanological processes that could induce fast underground mass redistributions, resulting in gravity changes at the surface. These processes involve bubbles and crystals present in the magma and require particular conditions in order to be effective as mass-redistributing processes. The gravity steps could be a geophysical evidence of the dynamical stress transfer between tectonic and magmatic systems at a local scale. Given the implications that these transfers may have on the volcanic activity, routine volcano monitoring should include the observation of fast gravity changes.
    Description: In press
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: open
    Keywords: gravity changes ; volcano ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.03. Geodesy::04.03.05. Gravity variations ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 32
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    An innovative tsunami detector operating in tsunami generation environment (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: On August 25th 2007 a tsunami detector installed onboard the multi-parameter observatory GEOSTAR was successfully deployed at 3200 b. s. l. in the Gulf of Cadiz, Portugal. This activity is within the NEAREST EC Project (http://nearest.bo.ismar.cnr.it/ ). Among other deliverables, the NEAREST project will produce and test the basic parts of an operational prototype of a near field tsunami warning system. This system includes an onshore warning centre, based on the geophysical monitoring networks which are already operating, and a tsunami detector deployed on board GEOSTAR at the sea bottom. On land the warning centre is in charge of collecting, integrating, and evaluating data recorded at sea. At the sea bottom data is recorded and processed by an advanced type of tsunami detector which includes: a pressure sensor, a seismometer and two accelerometers. The detector communicates acoustically with a surface buoy in two-way mode. The buoy is equipped with meteo station, GPS and tiltmeter and is connected to a shore station via satellite link. The prototype is designed to operate in tsunami generation areas for detection-warning purpose as well as for scientific measurements. The tsunami detector sends a near real time automatic alert message when a seismic or pressure threshold are exceeded. Pressure signals are processed by the tsunami detection algorithm and the water pressure perturbation caused by the seafloor motion is taken into account. The algorithm is designed to detect small tsunami waves, less than one centimetre, in a very noisy environment. Our objective is to combine a novel approach to the tsunami warning problem, with a study of the coupling between the water column perturbations and sea floor motion, together with the long term monitoring of geophysical, geochemical and oceanographic parameters.
    Description: Published
    Description: San Francisco, CA, USA
    Description: 1.8. Osservazioni di geofisica ambientale
    Description: open
    Keywords: Tsunamis and storm surges ; Seismic instruments and networks ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Poster session
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  • 33
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    Mineralogical, geochemical, and isotopic characteristics of the ejecta from the 5 April 2003 paroxysm at Stromboli, Itlay: Inferences on the Preeruptive Magma Dynamics (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: The 5 April 2003 explosive eruption at Stromboli emplaced typical basaltic scoria, pumice, and lithic blocks. This paper reports a detailed set of mineralogical, geochemical, and isotopic data on the juvenile ejecta and fresh subvolcanic blocks, including micro-Sr isotope analyses and major and dissolved volatile element contents in olivine-hosted melt inclusions. The juvenile ejecta have compositions similar to those of their analogs from previous paroxysms; the 2003 pumice, however, does not contain stable high-MgO olivine, usually typical of large-scale paroxysms and has lower compatible element contents. Texture, composition, and Sr isotope disequilibrium of crystals in pumice indicate that most of them are inherited from the shallow crystal-rich magma and/or crystal mush. The most primitive magma is recorded as rare melt inclusion in olivine Fo85–86. It has a typical S/Cl (1.1) and a total volatile content of 3.1 wt % from which the total fluid pressure was evaluated ≥240 MPa. Hence, moderate pressure conditions can be envisaged for the mechanism triggering the April 2003 paroxysm. The subvolcanic blocks are shoshonitic basalts with 45–50 vol % of phenocrysts (plagioclase + clinopyroxene + olivine). The late-stage crystallization of the crystal-rich magma lead to the formation of Na-sanidine with plagioclase An60–25 + olivine Fo68–49 + Timagnetite ± apatite ± phlogopite ± ilmenite assemblage. Mineralogy, chemistry, and Sr–Nd isotopic signatures of the subvolcanic blocks indicate they represent the slowly cooled equivalents of batches of crystal-rich basaltic magma stored in the uppermost subvolcanic feeding system. Cooling might be facilitated by short breaks in the summit crater activity.
    Description: Unpublished
    Description: 17
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: open
    Keywords: Stromboli volcano ; Paroxysmal activity ; Basaltic pumice ; Volatile content ; Mineralogy ; Geochemistry ; Sr isotope ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.04. Geology::04.04.07. Rock geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 34
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    Scanning tomography of SO2 distribution in a volcanic gas plume (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: Two-dimensional cross sections of the sulphur dioxide (SO2) distribution in the volcanic gas plume of Mt. Etna were reconstructed using tomographic techniques. The data for these projections were generated by a network of five automated scanning spectrometers, positioned on the flanks of the volcano. These measure slant-column amounts of SO2 at 105 different angles, every four minutes. Stable wind conditions allow the plume to be monitored on 82% of days. A time-series of plume cross sections was computed, revealing the potential of this method to track variations in plume position and structure on timescales of minutes to hours, a result of potential importance for air traffic and civil defence in case of eruption, when copious amounts of fine ash can be transported.
    Description: Published
    Description: L17811
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: tomography ; SO2 ; DOAS ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 35
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    Active tectonics of the Adriatic region from GPS and earthquake slip vectors (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: To investigate the kinematics of the Adriatic region we integrate continuous and episodic GPS measurements and ${M_w} 〉 4.5$ earthquake slip vectors selected from the Regional Centroid Moment Tensor (RCMT) catalogue. Coherent motion of GPS sites in the Po Valley, in Apulia and in the Hyblean Plateau allows us to estimate geodetically constrained angular velocities for these regions. The predictions of the GPS-inferred angular velocities are compared with the earthquake slip vectors, showing that the seismically-expressed deformation at the microplate boundaries is consistent with the observed geodetic motion. The remarkable consistency between geodetic, seismological and geological evidence of active tectonics, suggests that active deformation in the Central Adriatic is controlled by the relative motion between the Adria and Apulia microplates. The microplates angular rotation rates are then compared with the rotation rates calculated with a simple block model supporting the hypotheses (1) that Apulia forms a single microplate with the Ionian Sea and possibly with the Hyblean region and (2) that Adria and Apulia rotate in such a way as to accommodate the Eurasia-Nubia relative motion. We suggest that the present-day microplate configuration follows a recent fragmentation of the Adriatic promontory that during the Neogene rigidly transferred the Africa motion to the orogenic belts that now surround the Adriatic region.
    Description: Published
    Description: B12413
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: reserved
    Keywords: Adria ; GPS ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations
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  • 36
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    Earthquake magnitude estimation from early radiated energy (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: From inspection of a large set of Japanese events, we investigate the scaling of the early radiated energy, inferred from the squared velocity integral (IV2) with the final magnitude of the event. We found that the energy can only discriminate whether the event has a magnitude larger or smaller than 5.8, and in the latter case it can allow for realtime magnitude estimation. However, by normalizing IV2 for the rupture area, the initial slip scales with the magnitude between 4 〈 M 〈 7 following the expected scaling laws. We show that the ratio between the squared peak displacement and IV2 is a proxy for the slip following the same scaling but it can be directly derived from the data, without any assumption on the rupture area. The scaling relationship between initial slip and magnitude can be used for early warning applications, when integrated in a probabilistic, evolutionary approach. Citation: Festa, G., A. Zollo, and M. Lancieri (2008), Earthquake magnitude estimation from early radiated energy, Geophys. Res. Lett., 35, L22307, doi:10.1029/ 2008GL035576.
    Description: Published
    Description: L22307
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: JCR Journal
    Description: reserved
    Keywords: Early Warning ; Rupture initiation ; Seimic Source ; Magnitude estimation ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 37
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    Insights on the seismogenic layer thickness from the upper crust structure of the Umbria-Marche Apennines (Central Italy) (2008)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: [1] We reconstruct the subsurface geology in a region of the northern Apennines (central Italy) where a protracted extensional sequence occurred in 1997–1998 with maximum magnitude M = 6.0. Our study is mainly based on the interpretation of three reprocessed seismic reflection profiles crossing the epicentral area, which constrain the subsurface geometry to a depth of about 12 km where most of the shallow seismicity occurs. Comparing the subsurface setting with accurately determined earthquake locations, we find that the seismicity is located entirely within the sedimentary cover and does not penetrate the underlying basement. This is explained by considering that the sedimentary cover is rather thick and composed of relatively strong lithologies (platform carbonates and evaporites), while the upper part of the basement consists of weak phyllites and siliciclastic rocks. This weak horizon is also evidenced by the low-Vp values measured in deep wells of the region. Its effect is to decouple the sedimentary cover from the crystalline basement, where only microseismicity occurs. Our study indicates that local structure and stratigraphy can significantly influence the distribution of seismicity within the upper crust, particularly in complex geological environments such as thrust-and-fold belts.
    Description: Published
    Description: TC1010
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: reserved
    Keywords: seismogenic layers, northern apennines ; B/D transition ; umbria-marche apennines ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones
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  • 38
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    The 5 April 2003 Explosion of Stromboli: Timing of Eruption Dynamics using Thermal Data (2008)
    American Geophysical Union
    Details
    Publication Date: 2020-02-24
    Description: Stromboli’s 5 April 2003 explosion sent an ash plume to 4 km and blocks to 2 km, representing one of the most powerful events over the last 100 years. A thermal sensor 450 m east of the vent and a helicopter-flown thermal camera captured the event dynamics allowing detailed reconstruction. This review links previous studies providing a complete collation and clarification of the actual event chronology, while showing how relatively inexpensive thermal sensors can be used to provide great insight into processes that cannot be observed from locations outside of the eruption cloud. The eruption progressed through four phases, comprised 29 discrete explosions and lasted 373 s. The opening phase (phase 1) comprised ~30 s of precursory ash emission, with stronger emission beginning after 17 s. This was abruptly terminated by the main blast of phase 2 which comprised emission of a rapidly expanding ash cloud followed, after 0.4 s, by a powerful jet with velocities of up to 320 m/s. A second explosive phase (phase 3) began 38 s later and involved ascent of a phoenix cloud and explosive emission above a lateral vent lasting 75 s. This was followed by a 175-s-long phase of weaker, pulsed emission. The eruption was terminated by a series of three explosions (phase 4) sending ash to ~600 m at velocities of 27-45 m/s and lasting 87 s. Together these results have shown that a low energy opening phase was followed by the highest energy phase. Each phase itself comprised groups of discrete explosions, with energy of the explosions diminishing during the two final phases.
    Description: Published
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: open
    Keywords: Thermal imaging ; Stromboli ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 39
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    Volcanic and seismic activity at Stromboli preceding the 2002-03 eruption (2008)
    American Geophysical Union
    Details
    Publication Date: 2020-02-24
    Description: Regular surveys with a PM695 FLIR thermal imaging camera from both the ground and from helicopter were conducted on Stromboli from October 2001. These measurements allow us to (i) examine changes in morphology of the summit craters produced by paroxystic explosions and (ii) track the increasing level of magma within the conduits of Stromboli that preceded and led to the 2002/03 effusive eruption. Two geophysical surveys in May and September/October 2002 demonstrated a clear increasing trend in the amplitude of VLP events, consistent with the presence of a higher magma column above the VLP source region. The observed increase in magma level was probably induced by an increase in the pressure of the magma feeding system at Stromboli, controlled by regional tectonic stress. The increased magma level induced strain on the uppermost part of the crater terrace, allowing an increase in soil permeability and therefore CO2 and Radon degassing. Eventually this stress caused the northeast flank of the craters to fracture, allowing lava to flood out at high effusion rates on 28th December. Regular surveys with the thermal imaging camera, combined with geophysical monitoring, are an invaluable addition to the armory of volcanologists attempting to follow the evolution of activity on active volcanoes.
    Description: Published
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: open
    Keywords: Thermal imaging ; Stromboli ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 40
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    Network of Superconducting Gravimeters Benefits a Number of Disciplines (2008)
    American Geophysical Union
    Details
    Publication Date: 2020-02-24
    Description: abstract - A global network of superconducting gravimeters (SGs) is compiling significant data for a range of important studies spamming a number of disciplines concerned with the Earth's gravity, tides, environment, and geodetics. .......
    Description: Published
    Description: 121-126
    Description: 1.8. Osservazioni di geofisica ambientale
    Description: N/A or not JCR
    Description: open
    Keywords: Gravity ; Gravimeters ; Geodynamics ; Tides ; 04. Solid Earth::04.02. Exploration geophysics::04.02.02. Gravity methods
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 41
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    The eruptive activity of 28 and 29 December 2002 (2008)
    American Geophysical Union
    Details
    Publication Date: 2020-02-24
    Description: At 18:20 of 28 December 2002 an eruptive vent opened on the NE flank of the Sciara del Fuoco at 600 m asl, marking the onset of the 2002-2003 eruptive crisis of Stromboli volcano. The first eruptive hours were characterized by mild spattering and effusive activity from the new vent and the summit vent at crater 1. Gravitational instability processes also determined the partial collapse of NE walls of the summit cone (crater 1). Pyroclastic material partly accumulated on the NE part of the Sciara, and partly flowed down slope and reached the sea at Spiaggia dei Gabbiani forming a ~ 4m-thick, reddish avalanche, that was soon covered by a lava flow emitted in the following hours (Lodato et al., 2007). In this paper, we describe the first hours of activity trough eyewitnesses’ reports, geophysical monitoring, field and laboratory studies and of the erupted pyroclastic material and lava flows. Daily temperature measurements were carried out on the avalanche deposit formed by the flow of scoria along the Sciara, using a handheld thermal camera mainly during helicopter surveys. A fast cooling rate was typical of the deposit surface, and a slow cooling rate was representative of its inner portion.
    Description: Published
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: open
    Keywords: Thermal imaging ; Stromboli ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 42
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    Evolution of the lava flow field by daily thermal and visible airborne surveys (2008)
    American Geophysical Union
    Details
    Publication Date: 2020-02-24
    Description: On 28 December 2002, an effusive flank eruption started at Stromboli volcano (Aeolian Islands, 15 Italy). This lasted until 22 July 2003 and produced two lava flow fields that were emplaced onto the 16 steep slopes of Sciara del Fuoco. The first flow field was fed by a vent that opened at 500 m 17 elevation and was active between 30 December 2002 and 15 February 2003. The second was 18 supplied by a vent at 670 m and was emplaced mainly between 15 February and 22 July 2003. Here 19 we review the lava flow field emplacement based on daily thermal and visual surveys. The variable 20 slopes on which the lava flowed yielded an uncommon flow field morphology. This resulted in a 21 lava shield in the proximal area where flow stacking and inflation caused piling up of lava due to the 22 relatively flat ground. The proximal area was characterized by a complex network of tumuli and 23 tube-fed flows associated. The medial-distal lava flow field was emplaced on an extremely steep 24 zone. This area showed persistent flow front crumbling, producing a debris field on which emplaced 25 lava flows formed lava channels with excavated debris levées. This eruption provided an exceptional 26 opportunity to examine the evolution of lava flow fields emplaced on steep slopes, and proved the 27 usefulness of thermal imagers for safe and efficient monitoring of the active lava flows. In addition, thermal monitoring allowed calculation of quantitative parameters, such as effusion rate, allowing constraint of the time varying nature of supply to this eruption.
    Description: Published
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: open
    Keywords: thermal imaging ; stromboli ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 43
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    Measurements of 220Rn and 222Rn and CO2 emissions in soil and fumarole gases on Mt. Etna volcano (Italy): Implications for gas transport and shallow ground fracture (2008)
    American Geophysical Union
    Details
    Publication Date: 2020-02-24
    Description: Measurements of 220Rn and 222Rn activity and of CO2 flux in soil and fumaroles were carried out on Mount Etna volcano in 2005–2006, both in its summit area and along active faults on its flanks. We observe an empirical relationship between (220Rn/222Rn) and CO2 efflux. The higher the flux of CO2, the lower the ratio between 220Rn and 222Rn. Deep sources of gas are characterized by high 222Rn activity and high CO2 efflux, whereas shallow sources are indicated by high 220Rn activity and relatively low CO2 efflux. Excess 220Rn highlights sites of ongoing shallow rock fracturing that could be affected by collapse, as in the case of the rim of an active vent. Depletion both in 220Rn and in CO2 seems to be representative of residual degassing along recently active eruptive vents.
    Description: This work was funded by the Istituto Nazionale di Geofisica e Vulcanologia (S.G., M.N.) and by the Dipartimento per la Protezione Civile (Italy), projects V3_6/28-Etna (M.N.) and V5/08-Diffuse degassing in Italy (S.G.), and NSF EAR 063824101 (K.W.W.S.).
    Description: Published
    Description: Q10001
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 4.5. Degassamento naturale
    Description: JCR Journal
    Description: reserved
    Keywords: radon ; thoron ; carbon dioxide ; rock stress ; gas transport ; Mount Etna ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data
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  • 44
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    The 5 April 2003 paroxysm at Stromboli: a review of geochemical observations (2008)
    American Geophysical Union
    Details
    Publication Date: 2018-02-01
    Description: This paper reviews the published geochemical variations observed during the 2002–2003 eruption at Stromboli volcano. At the end of 2002, a new eruption began at Stromboli with a lava flow that lasted until the end of July 2003. On 5 April 2003 an explosive paroxysm occurred with the ejection of bombs that reached the village of Ginostra, about 4 km from the craters. During the eruption, specific variations in chemical composition of ground waters and summit fumaroles were recorded before the explosion, most of them for the first time. The water pH decreased significantly (0.5 units) and the dissolved CO2 increased in two thermal wells (Cusolito and Zurro) located near Stromboli harbor from March until 5 April. Peaks in the dissolved He were also observed at all the sampling sites. All of these changes in the thermal aquifer suggested a pressurization of the system due to the degassing of a volatile-rich magma at depth. In the summit area the SO2/HCl and SO2/HF ratios in the plume increased suddenly between 1 and 3 April due to the degassing of an S-rich magma that was approaching the shallow levels of the plumbing system, and this was involved in the explosion that occurred a few days later. This eruption was the first at Stromboli to be analyzed using geochemical models. The variations observed in the basal aquifer and in the summit area occurred on very different timescales: a few weeks and few days, respectively.
    Description: Published
    Description: 347-358
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: open
    Keywords: paroxysm ; geochemical observations ; monitoring ; plume ; thermal aquifer ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 45
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    Shades of White: Explaining Variations in Clear-Sky Snow Albedo (2008)
    American Geophysical Union
    In:  EPIC3American Geophysical Union, Fall Meeting 2008, American Geophysical Union, 2008A(abstra)
    Details
    Publication Date: 2019-12-03
    Description: Multi-year data from four Antarctic automatic weather stations show that clear-sky snow albedo ranges from 0.77 to 0.88, varying in time and space. The broadband albedo of a snowpack under clear-sky conditions is largely determined by snow grain size, solar zenith angle, and the vertical composition of the atmosphere -- but it is not obvious which process contributes what. A model that describes broadband radiative transfer in both the atmosphere and the snowpack is used to show that the observed variations in clear-sky snow albedo is dominated by strong spatial and temporal variation in snow grain size. Average values of snow grain size range from 22 μm on the Antarctic plateau to 64 μm on the ice shelves, whereas maximum values (December, January) are 40--150% higher. The seasonal cycle in solar zenith angle explains at most 0.02 of albedo variation at a location, whereas spatial variation in the atmospheric optical thickness leads to a 0.01 difference between plateau and ice shelf albedos. The most critical success factor for this method is the quality of the radiation observations, which is most notably affected by the horizontal tilt of either the radiation sensors or the snow surface. In order to tie model and observations together, we carried out an experiment at Summit, Greenland, where we simultaneously measured albedos and snow grain sizes, about which results will be presented.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , notRev
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  • 46
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    Tropospheric Comparisons of Vaisala Radiosondes and Balloon-Borne Frost-Point and Lyman-α Hygrometers during the LAUTLOS-WAVVAP Experiment (2008)
    American Meteorological Society
    In:  EPIC3Journal of Atmospheric and Oceanic Technology, American Meteorological Society, 25(2), pp. 149-166, ISSN: 0739-0572
    Details
    Publication Date: 2019-07-17
    Description: The accuracy of all types of Vaisala radiosondes and two types of Snow White chilled-mirror hygrosondes was assessed in an intensive in situ comparison with reference hygrometers. Fourteen nighttime reference comparisons were performed to determine a working reference for the radiosonde comparisons. These showed that the night version of the Snow White agreed best with the references [i.e., the NOAA frost-point hygrometer (FPH) and University of Colorado cryogenic frost-point hygrometer (CFH)], but that the daytime version had severe problems with contamination in the humid upper troposphere. Since the RS92 performance was superior to the other radiosondes and to the day version of the Snow White, it was selected to be the working reference. According to the reference comparison, the RS92 has no bias in the mid- and lower troposphere, with deviations 〈±5% in relative humidity (RH). In the upper troposphere, the RS92 has a 5% RH wet bias, which is partly due to the RS92 time lag error and the termination of the heating cycle. It was shown that the time lag effects relating to Vaisala radiosondes can be corrected. Because these were nighttime comparisons, they can be considered to be free from solar radiation effects. Neither the radiosondes nor the Snow White succeeded in reproducing reference class hygrometer profiles in the stratosphere. According to the 29 radiosonde intercomparisons, the RS92 and the modified RS90 (FN) had the best mutual agreement and no bias. The disagreement is largest (〈±10% RH) at low temperatures (T ≪ −30°C), where the FN underestimated (overestimated) in high (low) ambient RH. In comparison with the RS92, the RS90 had a semilinearly increasing wet bias with decreasing temperature, where the bias was 10% RH at −60°C. The RS80-A suffers from a large temperature-dependent dry bias in high RH conditions, being over 30% RH at −60°C and 5% RH near 0°C. The RS80-A dry bias can be almost totally removed with the correction algorithm by Leiterer et al., which was chosen as the best available. The other approach tested tends to overcorrect in high RH conditions when T 〈 −50°C. For T 〉 −30°C it is ineffective and does not correct the RS80-A dry bias in high ambient RH.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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    Estimating pore-space gas hydrate saturations from well log acoustic data (2008)
    American Geophysical Union
    Details
    Publication Date: 2022-05-25
    Description: This paper is not subject to U.S. copyright. The definitive version was published in Geochemistry Geophysics Geosystems 9 (2008): Q07008, doi:10.1029/2008GC002081.
    Description: Relating pore-space gas hydrate saturation to sonic velocity data is important for remotely estimating gas hydrate concentration in sediment. In the present study, sonic velocities of gas hydrate–bearing sands are modeled using a three-phase Biot-type theory in which sand, gas hydrate, and pore fluid form three homogeneous, interwoven frameworks. This theory is developed using well log compressional and shear wave velocity data from the Mallik 5L-38 permafrost gas hydrate research well in Canada and applied to well log data from hydrate-bearing sands in the Alaskan permafrost, Gulf of Mexico, and northern Cascadia margin. Velocity-based gas hydrate saturation estimates are in good agreement with Nuclear Magneto Resonance and resistivity log estimates over the complete range of observed gas hydrate saturations.
    Keywords: Methane hydrate ; Seismic velocity ; Hydrate assessment
    Repository Name: Woods Hole Open Access Server
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    Kinematics of slab tear faults during subduction segmentation and implications for Italian magmatism (2008)
    American Geophysical Union
    Details
    Publication Date: 2022-05-04
    Description: Tectonic activity in convergent plate boundaries commonly involves backward migration (rollback) of narrow subducting slabs and segmentation of subduction zones through slab tearing. Here we investigate this process in the Italian region by integrating seismic tomography data with spatiotemporal analysis of magmatic rocks and kinematic reconstructions. Seismic tomography results show gaps within the subducting lithosphere,which are interpreted as deep (100–500 km) subvertical tear faults. The development of such tear faults is consistent with proposed kinematic reconstructions, inwhich different rates of subduction rollback affected different parts of the subduction zone. We further suggest a possible link between the development of tear faults and the occurrence of regional magmatic activity with transitional geochemical signatures between arc type and OIB type, associated with slab tearing and slab breakoff.We conclude that lithospheric-scale tear faults play a fundamental role in the destruction of subduction zones. As such, they should be incorporated into reconstructions of ancient convergent margins, where tear faults are possibly represented by continental lineaments linked with magmatism and mineralization.
    Description: Published
    Description: TC2008
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: SLAB ; TEAR FAULTS ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    Physical property changes in hydrate-bearing sediment due to depressurization and subsequent repressurization (2008)
    American Geophysical Union
    Details
    Publication Date: 2022-05-26
    Description: This paper is not subject to U.S. copyright. The definitive version was published in Journal of Geophysical Research 113 (2008): B07102, doi:10.1029/2007JB005351.
    Description: Physical property measurements of sediment cores containing natural gas hydrate are typically performed on material exposed, at least briefly, to non-in situ conditions during recovery. To examine the effects of a brief excursion from the gas-hydrate stability field, as can occur when pressure cores are transferred to pressurized storage vessels, we measured physical properties on laboratory-formed sand packs containing methane hydrate and methane pore gas. After depressurizing samples to atmospheric pressure, we repressurized them into the methane-hydrate stability field and remeasured their physical properties. Thermal conductivity, shear strength, acoustic compressional and shear wave amplitudes, and speeds of the original and depressurized/repressurized samples are compared. X–ray computed tomography images track how the gas-hydrate distribution changes in the hydrate-cemented sands owing to the depressurizaton/repressurization process. Because depressurization-induced property changes can be substantial and are not easily predicted, particularly in water-saturated, hydrate-bearing sediment, maintaining pressure and temperature conditions throughout the core recovery and measurement process is critical for using laboratory measurements to estimate in situ properties.
    Description: U. S. Geological Survey contributions were supported by the Gas Hydrate Project of the U. S. Geological Survey’s Coastal and Marine Geology Program, in addition to Department of Energy contract DE-AI21-92MC29214. CT scanning at the Lawrence Berkeley National Laboratory was artfully performed by L. Tomutsa and supported by the Assistant Secretary for Fossil Energy, Office of Oil and Natural Gas, through the National Energy Technology Laboratory of the U. S. Department of Energy under contract DE-AC02-05CH11231.
    Keywords: Gas hydrate ; Physical properties ; Pressure core
    Repository Name: Woods Hole Open Access Server
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    The paroxysmal event and its deposits (2008)
    American Geophysical Union
    Details
    Publication Date: 2023-01-16
    Description: The 5 April 2003 eruption of Stromboli volcano (Italy) was the most violent in the past 50 years. It was also the best documented due to the accurate geophysical monitoring of the ongoing effusive eruption. Detailed field studies carried out a few hours to a few months after the event provided further information that were coupled with visual documentation to reconstruct the explosive dynamics. The eruption consisted of an 8-min-long explosive event preceded by a short-lived precursory activity that evolved into the impulsive ejection of gas and pyroclasts. Meter-sized ballistic blocks were launched to altitudes of up to 1400 m above the craters falling on the volcano flanks and on the village of Ginostra, about 2 km far from the vent. The vertical jet of gas and pyroclasts above the craters fed a convective plume that reached a height of 4 km. The calculated erupted mass yielded values of 1.1–1.4 × 108 kg. Later explosions generated a scoria flow deposit, with an estimated mass of 1.0–1.3 × 107 kg. Final, waning ash explosions closet the event. The juvenile fraction consisted of an almost aphyric, highly vesicular pumice mingled with a shallow-derived, crystal-rich, moderately vesicular scoria. Resuming of the lava emission a few hours after the paroxysm indicate that the shallow magmatic system was not significantly modified during the explosions. Combination of volume data with duration of eruptive phases allowed us to estimate the eruptive intensity: during the climactic explosive event, the mass discharge rate was between 106 and 107 kg/s, whereas during the pyroclastic flow activity, it was 2.8–3.6 × 105 kg/s. Strong similarities with other historical paroxysms at Stromboli suggest similar explosion dynamics.
    Description: Unpublished
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: open
    Keywords: Stromboli ; paroxysm ; explosive dynamics ; pyroclastic deposits ; ballistic ejecta ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    Dynamical Diagnosis: A Comparison of Quasigeostrophy and Ertel Potential Vorticity (2008)
    American Meteorological Society
    Details
    Publication Date: 2008-11-01
    Description: Advances in computer power, new forecasting challenges, and new diagnostic techniques have brought about changes in the way atmospheric development and vertical motion are diagnosed in an operational setting. Many of these changes, such as improved model skill, model resolution, and ensemble forecasting, have arguably been detrimental to the ability of forecasters to understand and respond to the evolving atmosphere. The use of nondivergent wind in place of geostrophic wind would be a step in the right direction, but the advantages of potential vorticity suggest that its widespread adoption as a diagnostic tool on the west side of the Atlantic is overdue. Ertel potential vorticity (PV), when scaled to be compatible with pseudopotential vorticity, is generally similar to pseudopotential vorticity, so forecasters accustomed to quasigeostrophic reasoning through the height tendency equation can transfer some of their intuition into the Ertel-PV framework. Indeed, many of the differences between pseudopotential vorticity and Ertel potential vorticity are consequences of the choice of definition of quasigeostrophic PV and are not fundamental to the quasigeostrophic system. Thus, at its core, PV thinking is consistent with commonly used quasigeostrophic diagnostic techniques.
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    Ensemble Synoptic Analysis (2008)
    American Meteorological Society
    Details
    Publication Date: 2008-11-01
    Description: Synoptic and mesoscale meteorology underwent a revolution in the 1940s and 1950s with the widespread deployment of novel weather observations, such as the radiosonde network and the advent of weather radar. These observations provoked a rapid increase in our understanding of the structure and dynamics of the atmosphere by pioneering analysts such as Fred Sanders. The authors argue that we may be approaching an analogous revolution in our ability to study the structure and dynamics of atmospheric phenomena with the advent of probabilistic objective analyses. These probabilistic analyses provide not only best estimates of the state of the atmosphere (e.g., the expected value) and the uncertainty about this state (e.g., the variance), but also the relationships between all locations and all variables at that instant in time. Up until now, these relationships have been determined by sampling in time by, for example, case studies, composites, and time-series analysis. Here the authors propose a new approach, ensemble synoptic analysis, which exploits the information contained in probabilistic samples of analyses at one or more instants in time. One source of probabilistic analyses is ensemble-based state-estimation methods, such as ensemble-based Kalman filters. Analyses from such a filter may be used to study atmospheric phenomena and the relationships between fields and locations at one or more instants in time. After a brief overview of a research-based ensemble Kalman filter, illustrative examples of ensemble synoptic analysis are given for an extratropical cyclone, including relationships between the cyclone minimum sea level pressure and other synoptic features, statistically determined operators for potential-vorticity inversion, and ensemble-based sensitivity analysis.
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    Closed Anticyclones of the Subtropics and Midlatitudes: A 54-Yr Climatology (1950–2003) and Three Case Studies (2008)
    American Meteorological Society
    Details
    Publication Date: 2008-11-01
    Description: The pioneering large-scale studies of cyclone frequency, location, and intensity conducted by Fred Sanders prompt similar questions about lesser-studied anticyclone development. The results of a climatology of closed anticyclones (CAs) at 200, 500, and 850 hPa, with an emphasis on the subtropics and midlatitudes, is presented to assess the seasonally varying distribution and hemispheric differences of these features. To construct the CA climatology, a counting program was applied to twice-daily 2.5° NCEP–NCAR reanalysis 200-, 500-, and 850-hPa geopotential height fields for the period 1950–2003. Stationary CAs, defined as those CAs that were located at a particular location for consecutive time periods, were counted only once. The climatology results show that 200-hPa CAs occur preferentially during summer over subtropical continental regions, while 500-hPa CAs occur preferentially over subtropical oceans in all seasons and over subtropical continents in summer. Conversely, 850-hPa CAs occur preferentially over oceanic regions beneath upper-level midocean troughs, and are most prominent in the Northern Hemisphere, and over midlatitude continents in winter. Three case studies of objectively identified CAs that produced heal waves over the United States, Europe, and Australia in 1995, 2003, and 2004, respectively, are presented to supplement the climatological results. The case studies, examining the subset of CAs than can produce heat waves, illustrate how climatologically hot continental tropical air masses produced over arid and semiarid regions of the subtropics and lower midlatitudes can become abnormally hot in conjunction with dynamically driven upper-level ridge amplification. Subsequently, these abnormally hot air masses are advected downstream away from their source regions in conjunction with transient disturbances embedded in anomalously strong westerly jets.
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    An Empirical Perspective on Cold Fronts (2008)
    American Meteorological Society
    Details
    Publication Date: 2008-11-01
    Description: Oklahoma Mesonetwork data are used to illustrate important atmospheric features that are not well shown by the usual synoptic data. For example, some shifts of wind from south to north that are shown as cold fronts on synoptic charts are not cold fronts by any plausible definition. As previously discussed by Fred Sanders and others, such errors in analysis can be reduced by knowledge of the wide variety of weather phenomena that actually exists, and by more attention to temperatures at the earth's surface as revealed by conventional synoptic data. Mesoscale data for four cases reinforce previous discussions of the ephemeral nature of fronts and deficiencies in the usual analyses of cold fronts. One type of misanalyzed case involves post-cold-frontal boundary layer air that is warmer than the prefrontal air. A second type is usually nocturnal, with a rise of local temperature during disruption of an inversion and a wind shift with later cooling that accompanies advection of a climatological gradient of temperature.
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    Back to Norway: An Essay (2008)
    American Meteorological Society
    Details
    Publication Date: 2008-11-01
    Description: The advent of the polar front theory of cyclones in Norway early in the last century held that the development of fronts and air masses is central to understanding midlatitude weather phenomena. While work on fronts continues to this day, the concept of air masses has been largely forgotten, superseded by the idea of a continuum. The Norwegians placed equal emphasis on the thermodynamics of airmass formation and on the dynamical processes that moved air masses around; today, almost all the emphasis is on dynamics, with little published literature on diabatic processes acting on a large scale. In this essay, the author argues that a lack of understanding of large-scale diabatic processes leads to an incomplete picture of the atmosphere and contributes to systematic errors in medium- and long-range weather forecasts. At the same time, modern concepts centered around potential vorticity conservation and inversion lead one to a redefinition of the term "air mass" that may have some utility in conceptualizing atmospheric physics and in weather forecasting.
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    Linking Weather and Climate (2008)
    American Meteorological Society
    Details
    Publication Date: 2008-11-01
    Description: Historically, the atmospheric sciences have tended to treat problems of weather and climate separately. The real physical system, however, is a continuum, with short-term (minutes to days) “weather” fluctuations influencing climate variations and change, and, conversely, more slowly varying aspects of the system (typical time scales of a season or longer) affecting the weather that is experienced. While this past approach has served important purposes, it is becoming increasingly apparent that in order to make progress in addressing many socially important problems, an improved understanding of the connections between weather and climate is required. This overview summarizes the progress over the last few decades in the understanding of the phenomena and mechanisms linking weather and climate variations. The principal emphasis is on developments in understanding key phenomena and processes that bridge the time scales between synoptic-scale weather variability (periods of approximately 1 week) and climate variations of a season or longer. Advances in the ability to identify synoptic features, improve physical understanding, and develop forecast skill within this time range are reviewed, focusing on a subset of major, recurrent phenomena that impact extratropical wintertime weather and climate variations over the Pacific–North American region. While progress has been impressive, research has also illuminated areas where future gains are possible. This article concludes with suggestions on near-term directions for advancing the understanding and capabilities to predict the connections between weather and climate variations.
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    Fred Sanders' Roles in the Transformation of Synoptic Meteorology, the Study of Rapid Cyclogenesis, the Prediction of Marine Cyclones, and the Forecast of New York City's “Big Snow” of December 1947 (2008)
    American Meteorological Society
    Details
    Publication Date: 2008-11-01
    Description: Fred Sanders' career extended over 55 yr, touching upon many of the revolutionary transformations in the field of meteorology during that period. In this paper, his contributions to the transformation of synoptic meteorology, his research into the nature of explosive cyclogenesis, and related advances in the ability to predict these storms are reviewed. In addition to this review, the current status of forecasting oceanic cyclones 4.5 days in advance is presented, illustrating the progress that has been made and the challenges that persist, especially for forecasting those extreme extratropical cyclones that are marked by surface wind speeds exceeding hurricane force. Last, Fred Sanders' participation in a forecast for the historic 1947 snowstorm (that produced snowfall amounts in the New York City area that set records at that time) is reviewed along with an attempt to use today's operational global model to simulate this storm using data that were available at the time. The study reveals the predictive limitations involved with this case based on the scarcity of upper-air data in 1947, while confirming Fred Sanders' forecasting skills when dealing with these types of major storm events, even as a young aviation forecaster at New York's LaGuardia Airport.
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    Finescale Radar Observations of a Dryline during the International H2O Project (IHOP_2002) (2008)
    American Meteorological Society
    Details
    Publication Date: 2008-11-01
    Description: A case study of a double dryline on 22 May 2002 is presented. Mobile, 3-mm-wavelength Doppler radars from the University of Massachusetts and the University of Wyoming (Wyoming cloud radar) were used to collect very fine resolution vertical-velocity data in the vicinity of each of the moisture gradients associated with the drylines. Very narrow (50–100 m wide) channels of strong upward vertical velocity (up to 8 m s–1) were measured in the convergence zone of the easternmost dryline, larger in magnitude than reported with previous drylines. Distinct areas of descending motion were evident to the east and west of both drylines. Radar data are interpreted in the context of other observational platforms available during the International H2O Project (IHOP-2002). a variational ground-based mobile radar data processing technique was developed and applied to pseudo-dual-Doppler data collected during a rolling range-height indicator deployment. It was found that there was a secondary (vertical) circulation normal to the easternmost moisture gradient; the circulation comprised an easterly component near-surface flow to the east, a strong upward vertical component in the convergence zone, a westerly return, flow above the convective boundary layer, and numerous regions of descending motion, the most prominent approximately 3–5 km to the east of the surface convergence zone.
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    The Application of Fred Sanders' Teaching to Current Research on Extreme Cold-Season Precipitation Events in the Saint Lawrence River Valley Region (2008)
    American Meteorological Society
    Details
    Publication Date: 2008-11-01
    Description: Fred Sanders' teaching and research contributions in the area of quasigeostrophic theory are highlighted in this paper. The application of these contributions is made to the topic of extreme cold-season precipitation events in the Saint Lawrence valley in the northeastern United States and southern Quebec. This research focuses on analyses of Saint Lawrence valley heavy precipitation events. Synoptic- and planetary-scale circulation anomaly precursors are typically identified several days prior to these events. These precursors include transient upper-level troughs, strong moisture transports into the region, and anomalously large precipitable water amounts. The physical insight of Fred Sanders' work is used in the analysis of these composite results. Further details of this insight are provided in analyses of one case of heavy precipitation.
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    The Sanders Barotropic Tropical Cyclone Track Prediction Model (SANBAR) (2008)
    American Meteorological Society
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    Publication Date: 2008-11-01
    Description: Sanders designed a barotropic tropical cyclone (TC) track prediction model for the North Atlantic TC basin that became known as the Sanders barotropic (SANBAR) model. It predicted the streamfunction of the deeplayer mean winds (tropical circulation vertically averaged from 1000 to 100 hPa) that represents the vertically averaged tropical circulations. Originally, the wind input for the operational objective analysis (OA) consisted of winds measured by radiosondes and 44 bogus winds provided by analysis at the National Hurricane Center (NHC), which corresponded to the vertically averaged flow over sparsely observed tropical, subtropical, and midlatitude oceanic regions. The model covered a fixed regional area and had a grid size of ~ 154 km. It estimated the initial storm motion solely on the basis of the large-scale flow from the OA, not taking into account the observed storm motion. During 1970, the SANBAR model became the first dynamical TC track model to be run operationally at NHC. Track forecasts of SANBAR were verified from the 1971 TC season when track model verifications began at NHC until its retirement after the 1989 Atlantic TC season. The average annual SANBAR forecast track errors were verified relative to Climatology and Persistence (CLIPER), the standard no-skill track forecast. Comparison with CLIPER determines the skill of track forecast methods. Verifications are presented for two different versions of the SANBAR model system used operationally during 1973–84 and 1985–89. In homogeneous comparisons (i.e., includes only forecasts for the same initial times) for the former period, SANBAR's track forecasts were slightly better than CLIPER at 24–48-h forecast intervals; however, from 1985 to 1989 the average SANBAR track forecast errors from 24–72 h were ~10% more skillful than homogeneous CLIPER track forecasts.
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    Surface Potential Temperature as an Analysis and Forecasting Tool (2008)
    American Meteorological Society
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    Publication Date: 2008-11-01
    Description: In the last decade, Fred Sanders was often critical of current surface analysis techniques. This led to his promoting the use of surface potential temperatures to distinguish between fronts, baroclinic troughs, and non-frontal baroclinic zones, and to the development of a climatology of surface baroclinic zones. In this paper, criticisms of current surface analysis techniques and the usefulness of surface potential temperature analyses are discussed. Case examples are used to compare potential temperature analyses and current National Centers for Environmental Prediction analyses. The 1-yr climatology of Sanders and Hoffman is reconstructed using a composite technique. Annual and seasonal mean potential temperature analyses over the continental United States, southern Canada, northern Mexico, and adjacent coastal waters are presented. In addition, gridpoint frequencies of moderate and strong potential temperature gradients are calculated. The results of the mean potential temperature analyses show that moderate and strong surface baroclinic zones are favored along the coastlines and the slopes of the North American cordillera. Additional subsynoptic details, not found in Sanders and Hoffman, are identified. The availability of the composite results allows for the calculation of potential temperature gradient anomalies. It is shown that these anomalies can be used to identify significant frontal baroclinic zones that are associated with weak potential temperature gradients. Together the results and reviews in this paper show that surface potential temperature analyses are a valuable forecasting and analysis tool allowing analysts to distinguish and identify fronts, baroclinic troughs, and nonfrontal baroclinic zones.
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    Surface Boundaries of the Southern Plains: Their Role in the Initiation of Convective Storms (2008)
    American Meteorological Society
    Details
    Publication Date: 2008-11-01
    Description: The nature of the different types of surface boundaries that appear in the southern plains of the United States during the convectively active season is reviewed. The following boundaries are discussed: fronts, the dryline, troughs, and outflow boundaries, The boundaries are related to their environment and to local topography. The role these boundaries might play in the initiation of convective storms is emphasized. The various types of boundary-related vertical circulations and their dynamics are discussed. In particular, quasigeostrophic and semigeostrophic dynamics, and the dynamics of solenoidal circulations, density currents, boundary layers, and gravity waves are considered. Miscellaneous topics pertinent to convective storms and their relationship to surface boundaries such as along-the-boundary variability, boundary collisions, and the role of vertical shear are also discussed. Although some cases of storm initiation along surface boundaries have been well documented using research datasets collected during comprehensive field experiments, much of what we know is based only on empirical forecasting and nowcasting experience. It is suggested that many problems relating to convective-storm formation need to be explored in detail using real datasets with new observing systems and techniques, in conjunction with numerical simulation studies, and through climatological studies.
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    Strong Surface Fronts over Sloping Terrain and Coastal Plains (2008)
    American Meteorological Society
    Details
    Publication Date: 2008-11-01
    Description: This paper begins with a review of basic surface frontogenesis concepts with an emphasis on fronts located over sloping terrain adjacent to mountain barriers and fronts located in large-scale baroclinic zones close to coastlines. The impact of cold-air damming and differential diabatic heating and cooling on frontogenesis is considered through two detailed case studies of intense surface fronts. The first case, from 17 to 18 April 2002, featured the westward passage of a cold (side-door) front across coastal eastern New England in which 15°–20°C temperature decreases were observed in less than one hour. The second case, from 28 February to 4 March 1972, featured a long-lived front that affected most of the United States from the Rockies to the Atlantic coast and was noteworthy for a 50°C temperature contrast between Kansas and southern Manitoba, Canada. In the April 2002 case most of New England was initially covered by an unusually warm, dry air mass. Dynamical anticyclogenesis over eastern Canada set the stage for a favorable pressure gradient to allow chilly marine air to approach coastal New England from the east. Diabatic cooling over the chilly (5°–8°C) waters of the Gulf of Maine allowed surface pressures to remain relatively high offshore while diabatic heating over the land (31°–33°C temperatures) enabled surface pressures to fall relative to over the ocean. The resulting higher pressures offshore resulted in an onshore cold push. Frontal intensity was likely enhanced prior to leaf out and grass green-up as virtually all of the available insolation went into sensible heating. The large-scale environment in the February–March 1972 case favored the accumulation of bitterly cold arctic air in Canada. Frontal formation occurred over northern Montana and North Dakota as the arctic air moved slowly southward in conjunction with surface pressure rises east of the Canadian Rockies. The arctic air accelerated southward subsequent to lee cyclogenesis–induced pressure falls ahead of an upstream trough that crossed the Rockies. The southward acceleration of the arctic air was also facilitated by dynamic anticyclogenesis in southern Canada beneath a poleward jet-entrance region. Frontal intensity varied diurnally in response to differential diabatic heating. Three types of cyclogenesis events were observed over the lifetime of the event: 1) low-amplitude frontal waves with no upper-level support, 2) low-amplitude frontal waves that formed in a jet-entrance region, and 3) cyclones that formed ahead of advancing upper-level troughs. All cyclones were either nondeveloping or weak developments despite extreme baroclinicity, likely the result of large atmospheric static stability in the arctic frontal zone and unfavorable alongfront stretching deformation. Significant frontal–mountain interactions were observed over the Rockies and the Appalachians.
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    The Fiftieth Anniversary of Sanders (1955): A Mesoscale Model Simulation of the Cold Front of 17–18 April 1953 (2008)
    American Meteorological Society
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    Publication Date: 2008-11-01
    Description: Over 50 yr have passed since the publication of Sanders' 1955 study, the first quantitative study of the structure and dynamics of a surface cold front. The purpose of this chapter is to reexamine some of the results of that study in light of modern methods of numerical weather prediction and diagnosis. A simulation with a resolution as high as 6-km horizontal grid spacing was performed with the fifth-generation-Pennsylvania State University-National Center for Atmospheric Research (PSU-NCAR) Mesoscale Model (MM5), given initial and lateral boundary conditions from the National Centers for Environmental Precipitation-National Center for Atmospheric Research (NCEP-NCAR) reanalysis project data from 17 to 18 April 1953. The MM5 produced a reasonable simulation af the front, albeit its strength was not as intense and its movement was not as fast as was analyzed by Sanders. The vertical structure of the front differed from that analyzed by Sanders in several significant ways. First, the strongest horizontal temperature gradient associated with the cold front in the simulation occurred above a surface-based inversion, not at the earth's surface. Second, the ascent plume at the leading edge of the front was deeper and more intense than that analyzed by Sanders. The reason was an elevated mixed layer that had moved over the surface cold front in the simulation, allowing a much deeper vertical circulation than was analyzed by Sanders. This structure is similar to that of Australian cold fronts with their deep, well-mixed, prefrontal surface layer. These two differences between the model simulation and the analysis by Sanders may be because upper-air data from Fort Worth, Texas, was unavailable to Sanders. Third, the elevated mixed layer also meant that isentropes along the leading edge of the front extended vertically. Fourth, the field of frontogenesis of the horizontal temperature gradient calculated from the three-dimensional wind differed in that the magnitude of the maximum of the deformation term was larger than the magnitude of the maximum of the tilting term in the simulation, in contrast to Sanders' analysis and other previously published cases. These two discrepancies may be attributable to the limited horizontal resolution of the data that Sanders used in constructing his cross section. Last, a deficiency of the model simulation was that the postfrontal surface superadiabatic layer in the model did not match the observed well-mixed boundary layer. This result raises the question of the origin of the well-mixed postfrontal boundary layer behind cold fronts. To address this question, an additional model simulation without surface fluxes was performed, producing a well-mixed, not superadiabatic, layer. This result suggests that surface fluxes were not necessary for the development of the well-mixed layer, in agreement with previous research. Analysis of this event also amplifies two research themes that Sanders returned to later in his career, First, a prefrontal wind shift occurred in both the observations and model simulation at stations in western Oklahoma. This prefrontal wind shift was caused by a lee cyclone departing the leeward slopes of the Rockies slightly equatorward of the cold front, rather than along the front as was the case farther eastward. Sanders' later research showed how the occurrence of these prefrontal wind shifts leads to the weakening of fronts. Second, this study shows the advantage of using surface potential temperature, rather than surface temperature, for determining the locations of the surface fronts on sloping terrain.
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    Must Surprise Snowstorms be a Surprise? (2008)
    American Meteorological Society
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    Publication Date: 2008-11-01
    Description: Today, even with state-of-the-art observational, data assimilation, and modeling systems run routinely on supercomputers, there are often surprises in the prediction of snowstorms, especially the “big ones,” affecting coastal regions of the mid-Atlantic and northeastern United States. Little did the author know that lessons from Fred Sanders' synoptic meteorology class at the Massachusetts Institute of Technology (1967) would later (late 1980s) inspire him to pursue practical issues of predictability in the context of the development of ensemble prediction systems, strategies, and applications for providing information on the inevitable case-dependent uncertainties in forecasts. This paper is a brief qualitative and somewhat colloquial overview, based upon this author's personal involvement and experiences, intended to highlight some basic aspects of the source and nature of uncertainties in forecasts and to illustrate the sort of value added information ensembles can provide in dealing with uncertainties in predictions of East Coast snowstorms.
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    Perspectives on Fred Sanders' Research on Cold Fronts (2008)
    American Meteorological Society
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    Publication Date: 2008-11-01
    Description: One characteristic of Fred Sanders' research is his ability to take a topic that is believed to be well understood by the research community and show that interesting research problems still exist. Among Sanders' considerable contributions to synoptic meteorology, those concerned with surface cold fronts have been especially influential. After a brief historical review of fronts and frontal analysis, this chapter presents three stages in Sanders' career when he performed research on the structure, dynamics, and analysis of surface cold fronts. First, his 1955 paper, "An investigation of the structure and dynamics of an intense surface frontal zone," was the first study to discuss quantitatively the dynamics of a surface cold front. In the 1960s, Sanders and his students further examined the structure of cold fronts, resulting in the unpublished 1967 report to the National Science Foundation, "Frontal structure and the dynamics of frontogenesis." For a third lime in his career, Sanders published several papers (1995–2005) revisiting the structure and dynamics of cold fronts. His 1967 and 1995–2005 work raises the question of the origin and dynamics of the surface pressure trough and/or wind shift that sometimes precedes the temperature gradient (hereafter called a prefrontal trough or prefrontal wind shift, respectively). Sanders showed that the relationship between this prefrontal feature and the temperature gradient is fundamental to the strength of the front. When the wind shift is coincident with the temperature gradient, frontogenesis (strengthening of the front) results; when the wind shift lies ahead of the temperature gradient, frontolysis (weakening of the front) results. a number of proposed mechanisms for the formation of prefrontal troughs and prefrontal wind shifts exist. Consequently, much research remains to be performed on these topics.
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    IRF8 regulates B-cell lineage specification, commitment, and differentiation (2008)
    American Society of Hematology
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    Publication Date: 2008-11-15
    Description: PU.1, IKAROS, E2A, EBF, and PAX5 comprise a transcriptional network that orchestrates B-cell lineage specification, commitment, and differentiation. Here we identify interferon regulatory factor 8 (IRF8) as another component of this complex, and show that it also modulates lineage choice by hematopoietic stem cells (HSCs). IRF8 binds directly to an IRF8/Ets consensus sequence located in promoter regions of Sfpi1 and Ebf1, which encode PU.1 and EBF, respectively, and is associated with transcriptional repression of Sfpi1 and transcriptional activation of Ebf1. Bone marrows of IRF8 knockout mice (IRF8−/−) had significantly reduced numbers of pre-pro-B cells and increased numbers of myeloid cells. Although HSCs of IRF8−/− mice failed to differentiate to B220+ B-lineage cells in vitro, the defect could be rescued by transfecting HSCs with wild-type but not with a signaling-deficient IRF8 mutant. In contrast, overexpression of IRF8 in HSC-differentiated progenitor cells resulted in growth inhibition and apoptosis. We also found that IRF8 was expressed at higher levels in pre-pro-B cells than more mature B cells in wild-type mice. Together, these results indicate that IRF8 modulates lineage choice by HSCs and is part of the transcriptional network governing B-cell lineage specification, commitment, and differentiation.
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    Restoration of Bone Balance Via Activin a Inhibition Results in Anti-Myeloma Activity (2008)
    American Society of Hematology
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    Publication Date: 2008-11-16
    Description: A distinct feature of multiple myeloma (MM) is the tight interaction between malignant plasma cells and their bone microenvironment, creating a niche suitable for MM growth. In particular, MM cells inhibit osteoblast (OB) differentiation and stimulate osteoclast (OC) function, resulting in imbalanced bone remodeling and osteolytic bone disease. Here we studied a novel cytokine, activin A, identified from a broad range of cytokines, in the development of MM bone disease. We next asked whether activin A inhibition could restore bone balance and suppress tumor growth. Activin, a member of the TNF-α superfamily, is a pleiotropic cytokine involved in bone remodeling. Here, we observed, that MM patients with multiple osteolytic lesions had a 4-fold increase in activin A expression levels in bone marrow plasma compared to MM patients with one or less osteolytic lesions and non-MM patients (average 123.6 ± 136 vs 26.4 ± 21.4 vs 30.6 ± 25.1 pg/ml respectively, p
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    High Response Rates with the Combination of Bortezomib, Dexamethasone and the Pan-Histone Deacetylase Inhibitor Romidepsin in Patients with Relapsed or Refractory Multiple Myeloma in a Phase I/II Clinical Trial (2008)
    American Society of Hematology
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    Publication Date: 2008-11-16
    Description: INTRODUCTION: Proteasome inhibitors (PI) and histone deacetylase inhibitors (HDACi) have demonstrated synergistic pre-clinical activity in multiple myeloma (MM). The goals of this study were to evaluate this combination regimen’s clinical activity and adverse events, including thrombocytopenia (TCP) since both drug classes may cause transient TCP. We performed an open label, single-centre, single-arm, phase I/II, dose-escalation trial of bortezomib, dexamethasone and romidepsin (depsipeptide) in relapsed or refractory MM. This is the first clinical trial to combine these 3 agents. METHODS. All patients (pts) received bortezomib (1.3mg/m2 d1, 4, 8, 11) with dexamethasone (20mg d1, 2, 4, 5, 8, 9, 11, 12). Romidepsin commenced at 8 mg/m2 IV d1, 8, and 15 every 28 days with a planned accelerated intra-patient dose escalation to 10, 12 and 14 mg/m2 (n=10). After CR + 2 cycles or a maximum of 8 cycles, pts with SD or better commenced maintenance (Mx) therapy, romidepsin at the MTD on days 1 and 8 of a 28 day cycle until PD. An additional 15 pts were treated at the MTD in a phase II expansion. Response was assessed after every 2 cycles according to IMWG criteria (with minimal Response (MR) defined as ≥25% but
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    Platelet-VWF complexes are preferred substrates of ADAMTS13 under fluid shear stress (2008)
    American Society of Hematology
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    Publication Date: 2008-01-15
    Description: Endothelial cells secrete prothrombotic ultralarge von Willebrand factor (VWF) multimers, and the metalloprotease ADAMTS13 cleaves them into smaller, less dangerous multimers. This reaction is stimulated by tensile force applied to the VWF substrate, which may occur on cell surfaces or in the circulating blood. The cleavage of soluble VWF by ADAMTS13 was accelerated dramatically by a combination of platelets and fluid shear stress applied in a cone-plate viscometer. Platelet-dependent cleavage of VWF was blocked by an anti-GPIbα monoclonal antibody or by a recombinant soluble fragment of GPIbα that prevents platelet-VWF binding. Multimeric gel analysis showed that shear and platelet-dependent cleavage consumed large VWF multimers. Therefore, ADAMTS13 preferentially acts on platelet-VWF complexes under fluid shear stress. This reaction is likely to account for a majority of VWF proteolysis after secretion and to determine the steady-state size distribution of circulating VWF multimers in vivo.
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    CREB is a critical regulator of normal hematopoiesis and leukemogenesis (2008)
    American Society of Hematology
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    Publication Date: 2008-02-01
    Description: The cAMP-responsive element binding protein (CREB) is a 43-kDa nuclear transcription factor that regulates cell growth, memory, and glucose homeostasis. We showed previously that CREB is amplified in myeloid leukemia blasts and expressed at higher levels in leukemia stem cells from patients with myeloid leukemia. CREB transgenic mice develop myeloproliferative disease after 1 year, but not leukemia, suggesting that CREB contributes to but is not sufficient for leukemogenesis. Here, we show that CREB is most highly expressed in lineage negative hematopoietic stem cells (HSCs). To understand the role of CREB in hematopoietic progenitors and leukemia cells, we examined the effects of RNA interference (RNAi) to knock down CREB expression in vitro and in vivo. Transduction of primary HSCs or myeloid leukemia cells with lentiviral CREB shRNAs resulted in decreased proliferation of stem cells, cell- cycle abnormalities, and inhibition of CREB transcription. Mice that received transplants of bone marrow transduced with CREB shRNA had decreased committed progenitors compared with control mice. Mice injected with Ba/F3 cells expressing either Bcr-Abl wild-type or T315I mutation with CREB shRNA had delayed leukemic infiltration by bioluminescence imaging and prolonged median survival. Our results suggest that CREB is critical for normal myelopoiesis and leukemia cell proliferation.
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    The incidence of and risk factors for venous thromboembolism (VTE) and bleeding among 1514 patients undergoing hematopoietic stem cell transplantation: implications for VTE prevention (2008)
    American Society of Hematology
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    Publication Date: 2008-08-01
    Description: Venous thromboembolism (VTE) is increasingly diagnosed among individuals with hematologic malignancies. However, the risk of VTE among patients undergoing hematopoietic stem cell transplantation (HSCT) is unclear. We examined the incidence and risk factors for VTE and bleeding among 1514 patients undergoing in-patient HSCT. No protocolized VTE prophylaxis was used. By HSCT day 180, 75 symptomatic VTE occurred in 70 patients (4.6%; 95% confidence interval [CI], 3.6%-5.8%). Fifty-five (3.6%) were catheter-associated, 11 (0.7%) were non–catheter-associated deep venous thromboses, and 9 (0.6%) were pulmonary emboli. Thirty-four percent of VTE occurred at a platelet count less than 50 ×109/L; 13% occurred at a platelet count less than 20 ×109/L. In multivariate analysis, VTE was associated with prior VTE (odds ratio [OR], 2.9; 95% CI, 1.3-6.6) and with graft-versus-host disease (GVHD; OR, 2.4; 95% CI, 1.4-4.0). Clinically significant bleeding occurred in 230 patients (15.2%; 95% CI, 13.4%-17.1%); 55 patients (3.6%; 95% CI, 2.7%-4.7%) had fatal bleeding. Bleeding was associated with anticoagulation (OR, 3.1; 95% CI, 1.8-5.5), GVHD (OR, 2.4; 95% CI, 1.8-3.3), and veno-occlusive disease (OR, 2.2; 95% CI, 1.4-3.6). In HSCT patients, VTE is primarily catheter-related and 3-fold less common than clinically significant bleeding. These findings warrant consideration when selecting VTE prophylaxis in HSCT patients.
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    Local production and activation of complement up-regulates the allostimulatory function of dendritic cells through C3a–C3aR interaction (2008)
    American Society of Hematology
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    Publication Date: 2008-02-15
    Description: Donor cell expression of C3 enhances the alloimmune response and is associated with the fate of transplantation. To clarify the mechanism for enhancement of the immune response, we have explored the role of C3a receptor (C3aR)–ligand interaction on murine bone marrow dendritic cells (DCs). We show that DCs either lacked receptor for C3a (a C3 cleavage product) or were treated with C3aR antagonist, elicited defective T-cell priming against alloantigen expressed on the DCs. This was associated with reduced surface expression of major histocompatibility complex (MHC) and costimulatory molecules on the DCs, and with defective priming in skin allograft rejection. In addition, DCs lacking factor B were unable to generate potent T-cell responses against donor antigen, whereas lack of C4 had no detectable effect, suggesting a role for the alternative pathway contributing to allostimulation. Furthermore, therapeutic complement regulator can down-regulate DC allostimulatory function. These findings suggest that the capacity of DCs for allostimulation depends on their ability to express, activate, and detect relevant complement components leading to C3aR signaling. This mechanism, in addition to underpinning the cell-autonomous action of donor C3 on allostimulation, has implications for a wider range of immune responses in self-restricted T-cell priming.
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    Parathyroid Hormones (PTH) Serum Variations Are Associated with Bortezomib Response in Multiple Myeloma Patients (2008)
    American Society of Hematology
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    Publication Date: 2008-11-16
    Description: A correlation between increase in bone markers (alkaline phosphatase (ALP) and response to bortezomib in patients with multiple myeloma (MM) has been previously described. We now report results from a prospective study examining the relationship of serum PTH variation with skeletal effects and myeloma response to bortezomib treatment. Methods: Single agent bortezomib (1.3 mg/m2 patients 1–10; 1mg/m2 patient 11–20), was administered to patients with relapsed/refractory MM on days 1, 4, 8 and 11 on a 21 day interval for a total of 3 cycles; patients were not allowed to receive concurrent bisphosphonates or any other anti-myeloma drugs during the study period. Dynamic indices of bone turnover were prospectively evaluated by high-resolution microCT. Architectural parameters such as bone volume/total volume (BVTV), trabecular number (TbN), and thickness (Tb.Th) was obtained. PTH along with bone markers (osteocalcin, calcium, magnesium, phosphorus and serum creatinine) were measured on days 1, 4, 8, 11 before and after each bortezomib dose and every 4 hours thereafter, daily for the other days of the treatment cycle. Results: Seventeen patients were enrolled in the study with a median age of 63 years, 41 % were male and 3/4 of the patients previously failed high-dose chemotherapy. Histomorphometric microCT comparative analysis was completed (baseline and post-treatment) in 7 of the 17 patients enrolled in the trial. Baseline BV/TV values ranged from 13% to 90%. After 3 cycles of bortezomib treatment a statistically significant increase in BV/TV was recorded in 6 of 7 patients (P
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    Monitoring of ADAMTS13 in Patients with Thrombotic Thrombocytopenic Purpura: Prediction of Response to Therapy, Risk of Relapse, and Long- Term Outcome. (2008)
    American Society of Hematology
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    Publication Date: 2008-11-16
    Description: A severely reduced ADAMTS13 activity due to inhibitory autoantibodies is a key feature of acquired thrombotic thrombocytopenic purpura (TTP), leading to the persistence of ultralarge VWF multimers, platelet aggregation and disturbance of microcirculation. We followed 39 patients (8 male, 31 female, mean age 38 years) with clinical signs of TTP over a period between 5 days to 16 years and observed a total of 53 episodes of TTP. ADAMTS13 was measured with a collagen-binding assay and the FRETS-VWF73 based Technozym ADAMTS-13 assay (activity and antigen, respectively). ADAMTS13 inhibitor was measured with a modified Bethesda method with both the above mentioned assays, and with the Technozym ADAMTS-13 INH ELISA. Thirty-one patients had autoimmune TTP, and 47 episodes of TTP were analyzed in these patients. In all acute episodes, ADAMTS13 activity was below the detection limit (0.2 U/ml in 66% of the episodes (after median 160 days). In the remaining cases anti-ADAMTS13 antibodies persisted during remissions for up to 2 years. In 3 cases the antibody reoccurred after initial normalization of ADAMTS13 activity, and clinical relapses followed. In total, 21 relapses were observed after a median of 46 months (range 1– 87), all associated with low ADAMTS13 levels. Rituximab was given in 7 cases of relapsing TTP and resulted in complete, durable clearance of the antibodies in 100%. Determination of ADAMTS13-related parameters is useful to distinguish between autoimmune, hereditary, and secondary forms of TTP and to choose an appropriate therapy. It is also useful to predict the risk of relapse in patients with TTP in remission.
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    The impact of JAK2 and MPL mutations on diagnosis and prognosis of splanchnic vein thrombosis: a report on 241 cases (2008)
    American Society of Hematology
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    Publication Date: 2008-05-15
    Description: Myeloproliferative diseases (MPDs) represent the commonest cause of splanchnic vein thrombosis (SVT), including Budd-Chiari syndrome (BCS) and portal vein thrombosis (PVT), but their diagnosis is hampered by changes secondary to portal hypertension, while their influence in the outcome of SVT remains unclear. We assessed the diagnostic and prognostic value of JAK2 and MPL515 mutations in 241 SVT patients (104 BCS, 137 PVT). JAK2V617F was found in 45% of BCS and 34% of PVT, while JAK2 exon 12 and MPL515 mutations were not detected. JAK2V617F was found in 96.5% of patients with bone marrow (BM) changes specific for MPD and endogenous erythoid colonies, but also in 58% of those with only one feature and in 7% of those with neither feature. Stratifying MPD diagnosis first on JAK2V617F detection would have avoided BM investigations in 40% of the patients. In BCS, presence of MPD carried significantly poorer baseline prognostic features, required hepatic decompression procedures earlier, but had no impact on 5-year survival. Our results suggest that JAK2V617F testing should replace BM investigations as initial test for MPD in patients with SVT. Underlying MPD is associated with severe forms of BCS, but current therapy appears to offset deleterious effects of MPD on the medium-term outcome.
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    Efficacy, Complication Rates, and Cost Effectiveness of Chemotherapy Plus Granulocyte Colony Stimulating Factor Conditioned Mobilisation of Peripheral Blood Haematopoietic Stem Cells in Over 150 Patients with Haematological Malignancies (2008)
    American Society of Hematology
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    Publication Date: 2008-11-16
    Description: Autologous stem cell transplantation (ASCT) remains the standard consolidation therapy for patients with multiple myeloma (MM) and chemosensitive relapsed lymphoma (r-Ly). Peripheral blood as a source of stem cells (PBSC) has largely replaced marrow and has the advantage of improved engraftment rates. PBSC are routinely collected following administration of chemotherapy in combination with GCSF. However, the resultant pancytopenia poses a significant risk to patients and additional chemotherapy prior to ASCT may lead to increased end organ damage potentially precluding future therapies (including ASCT). Novel agents can achieve PBSC mobilisation without the use of cytotoxics. In the advent of such drugs, we reviewed the efficacy of, and complications experienced by patients during PBSC mobilisation. We also analysed the cost implications of adverse events. Of 151 consecutive attempts, 13.2% of patients failed to reach our criteria in order to attempt pheresis (1 × 104 CD34 cells/ml). Of those achieving target and undergoing pheresis, 6% did not achieve an adequate cell dose for future ASCT (2 × 106CD34+cells/kg) giving an overall failure rate of 19.2%. Furthermore 17.9% failed to harvest our ideal of 4 × 106/kg (permitting 〉1 ASCT procedure). Factors contributing to failure in achieving target CD34+ve PB count on univariate analysis were; 〉2 lines of previous chemotherapy and occurrence of neutropenic sepsis (NS (p=0.002, and 0.005 respectively). These factors remained significant on multivariate analysis (RR: 4.4 and 6.2). These same factors also affected CD34+ cell yield on both univariate and multivariate analysis (RR: 3.3 and 4.6). No differences were seen between MM and r-Ly. Overall, the complication rate was 34.4%, with 24.1% of patients suffering NS requiring admission. The mortality rate was 1.3% (NS and intra-cranial bleed). Of those developing NS, only 52% eventually harvested sufficient cells, but with a median delay of 3 days. The median cost of PBSC collection was $17,381.46 ($1,978.97–$39,355.73). NS significantly increased the cost of mobilisation at a median cost of $25,532.95 vs $16,4921) (p=
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    Resolvin E1, an EPA-derived mediator in whole blood, selectively counterregulates leukocytes and platelets (2008)
    American Society of Hematology
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    Publication Date: 2008-08-01
    Description: Resolvin E1 (RvE1) is an omega-3 eicosapentaenoic acid (EPA)–derived lipid mediator generated during resolution of inflammation and in human vasculature via leukocyte-endothelial cell interactions. RvE1 possesses anti-inflammatory and proresolving actions. Here, we report that RvE1 in human whole blood rapidly regulates leukocyte expression of adhesion molecules. RvE1 in the 10- to 100-nM range stimulated L-selectin shedding, while reducing CD18 expression in both neutrophils and monocytes. When added to whole blood, RvE1 did not stimulate reactive oxygen species by either neutrophils or monocytes, nor did it directly stimulate cytokine/chemokine production in heparinized blood. Intravital microscopy (IVM) demonstrated that RvE1 rapidly reduced leukocyte rolling (∼ 40%) in venules of mice. In human platelet-rich plasma (PRP), RvE1 selectively blocked both ADP-stimulated and thromboxane receptor agonist U46619-stimulated platelet aggregation in a concentration-dependent manner. In contrast, Δ6,14-trans-RvE1 isomer was inactive. RvE1 did not block collagen-stimulated aggregation, and regulation of ADP-induced platelet aggregation was not further enhanced with aspirin treatment. These results indicate RvE1 is a potent modulator of leukocytes as well as selective platelet responses in blood and PRP, respectively. Moreover, the results demonstrate novel agonist-specific antiplatelet actions of RvE1 that are potent and may underlie some of the beneficial actions of EPA in humans.
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    Catheter Related Bloodstream Infection in Haematological Patients: A Prospective, Randomized Study Comparing Heparin-Coated with Chlorhexidine and Silver Sulfadiazine Impregnated Central Venous Catheters (2008)
    American Society of Hematology
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    Publication Date: 2008-11-16
    Description: Central venous catheters (CVCs) are widely used in patients with hemato-oncological disease for indications such as administration of chemotherapy, parenteral nutrition, blood products and monitoring of hemodynamics. CVCs are a major source of hospital-acquired infection. The National Nosocomial Infections Surveillance System reported a rate of catheter-related bloodstream infection (CRBI) of five per 1000 central catheter-days. This study was a randomized trial in which patients with nontunneled catheters were randomly assigned to heparin-coated (7 French, polyurethane, double lumen; Arrow®, USA) or chlorhexidine and silver sulfadiazine impregnated CVCs (7 French, polyurethane, double lumen; Arrow®, USA). All CVCs were placed in the subclavian vein in the operating room. CRBI was defined according to Infectious Disease Society of America guidelines. The principal investigator determined whether infections were catheter related and had no knowledge of “the assigned arm” at the time of adjudication of the reference standard definition. Before catheter insertion, laboratory prothrombotic markers included factor V Leiden, the prothrombin gene Gly20210A mutation, plasma antithrombin levels, and protein C and S activity. In our study, all patients were systematically examined by ultrasonography just before, or less than 24 hours after, catheter removal and in case of clinical signs of thrombosis. Two radiologists performed the ultrasonography and were unaware of the allocation of the patients. Two hundred and twenty patients were randomly assigned. Eight patients were excluded after assignment. Ultimately, 212 patients were analyzed [median age: 28 years (7–60); 97 female and 115 male]. CRBI occurred in 6.7% (7/104) of those in the heparin-coated group (2.7 events per 1000 days) and in 4.6% (5/108) in the chlorhexidine and silver sulfadiazine group (2 events per 1000 days) (P=0.5). The microorganisms involved in CRBIs were coagulase-negative Staphylococcus (five cases in the heparin group and 3 cases in the antiseptic group), Staphylococcus aureus (one case in the heparin group), Candida parapsilosis (one case in the antiseptic group), Pseudomonas aeruginosa (one case in the heparin group and one case in the antiseptic group). We observed a CVC-related thrombosis in 11 patients (5.2%; 5 in the heparin group and 6 in the antiseptic group P=0.8). Catheter-related thrombosis and CRBI coincided in two patients and were not significantly correlated (P=0.6). Four (1.9%) and three (1.4%) patients had evidence of protein C and protein S deficiency, respectively. Only one patient had an antithrombin deficiency (0.5%). In total, 9 patients (4.2%) were heterozygous for the factor V Leiden mutation. Thrombosis was diagnosed in three out of 17 patients (17.6%) with a inherited prothrombotic abnormality compared to 8 out of 195 patients (4.1%) who did not have a thrombophilic marker (relative risk 4.3 CI 95% 1.2–14.7). Six and five patients experienced severe bleeding in the heparin and antiseptic groups, respectively. We did not observe heparin-induced thrombocytopenia and anaphylaxis to chlorhexidine was not reported. To our knowledge, this is the first randomized study comparing in haematological patients heparin-coated with antiseptic impregnated CVCs. Furthermore, our results suggest that inherited prothrombotic abnormalities contribute substantially to CVC-related thrombosis in hemato-oncological patients. Presently, the best options for reducing CRBI are heparin-coated and antibiotic-impregnated CVCs. A large, well designed randomized controlled trial is required to determine which of these is most effective.
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    Chemokine-mediated rapid turnover of myeloid-derived suppressor cells in tumor-bearing mice (2008)
    American Society of Hematology
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    Publication Date: 2008-06-15
    Description: Tumor growth is associated with aberrant myelopoiesis, including the accumulation of CD11b+Gr-1+ myeloid-derived suppressor cells (MDSCs) that have the potential to promote tumor growth. However, the identity, growth, and migration of tumor-associated MDSCs remain undefined. We demonstrate herein that MDSCs at tumor site were composed primarily of bone marrow-derived CD11b+Gr-1hiLy-6Cint neutrophils and CD11b+Gr-1int/dullLy-6Chi macrophages. Unexpectedly, in vivo bromodeoxyuridine (BrdU) labeling and parabiosis experiments revealed that tumor-infiltrating macrophages were replenished more rapidly than neutrophils. CCR2 deficiency caused striking conversion of infiltrating cellular dominance from macrophages to neutrophils in the tumor with the excessive production of CXCR2 ligands and granulocyte-colony stimulating factor in the tumor without affecting tumor growth. Overall, our data established the identity and dynamics of MDSCs in a tumor-bearing host mediated by chemokines and elucidated unexpected effects of the paucity of macrophages on tumor development.
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    Cell functions impaired by frataxin deficiency are restored by drug-mediated iron relocation (2008)
    American Society of Hematology
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    Publication Date: 2008-12-15
    Description: Various human disorders are associated with misdistribution of iron within or across cells. Friedreich ataxia (FRDA), a deficiency in the mitochondrial iron-chaperone frataxin, results in defective use of iron and its misdistribution between mitochondria and cytosol. We assessed the possibility of functionally correcting the cellular properties affected by frataxin deficiency with a siderophore capable of relocating iron and facilitating its metabolic use. Adding the chelator deferiprone at clinical concentrations to inducibly frataxin-deficient HEK-293 cells resulted in chelation of mitochondrial labile iron involved in oxidative stress and in reactivation of iron-depleted aconitase. These led to (1) restoration of impaired mitochondrial membrane and redox potentials, (2) increased adenosine triphosphate production and oxygen consumption, and (3) attenuation of mitochondrial DNA damage and reversal of hypersensitivity to staurosporine-induced apoptosis. Permeant chelators of higher affinity than deferiprone were not as efficient in restoring affected functions. Thus, although iron chelation might protect cells from iron toxicity, rendering the chelated iron bioavailable might underlie the capacity of deferiprone to restore cell functions affected by frataxin deficiency, as also observed in FRDA patients. The siderophore-like properties of deferiprone provide a rational basis for treating diseases of iron misdistribution, such as FRDA, anemia of chronic disease, and X-linked sideroblastic anemia with ataxia.
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    The hematopoietic stem cell compartment of JAK2V617F-positive myeloproliferative disorders is a reflection of disease heterogeneity (2008)
    American Society of Hematology
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    Publication Date: 2008-09-15
    Description: The JAK2V617F somatic point mutation has been described in patients with myeloproliferative disorders (MPDs). Despite this progress, it remains unknown how a single JAK2 mutation causes 3 different MPD phenotypes, polycythemia vera (PV), essential thrombocythemia, and primitive myelofibrosis (PMF). Using an in vivo xenotransplantation assay in nonobese diabetic-severe combined immunodeficient (NOD/SCID) mice, we tested whether disease heterogeneity was associated with quantitative or qualitative differences in the hematopoietic stem cell (HSC) compartment. We show that the HSC compartment of PV and PMF patients contains JAK2V617F-positive long-term, multipotent, and self-renewing cells. However, the proportion of JAK2V617F and JAK2 wild-type SCID repopulating cells was dramatically different in these diseases, without major modifications of the self-renewal and proliferation capacities for JAK2V617F SCID repopulating cells. These experiments provide new insights into the pathogenesis of JAK2V617F MPD and demonstrate that a JAK2 inhibitor needs to target the HSC compartment for optimal disease control in classical MPD.
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    Effects of Age, Weight, Gender and Renal Function in a Pooled Analysis of Four Phase III Studies of Rivaroxaban for Prevention of Venous Thromboembolism after Major Orthopedic Surgery (2008)
    American Society of Hematology
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    Publication Date: 2008-11-16
    Description: The RECORD program comprised four pivotal phase III trials comparing the oral direct Factor Xa inhibitor, rivaroxaban, with subcutaneous enoxaparin for the prevention of venous thromboembolism (VTE) after total hip and knee replacement (THR and TKR). A total of 12,729 patients were randomized to receive rivaroxaban 10 mg once daily (od) starting 6–8 hours after surgery, or enoxaparin 40 mg od (RECORD1–3) starting the evening before surgery, or 30 mg every 12 hours (RECORD4) starting 12–24 hours after surgery. In RECORD1, patients undergoing THR received extended prophylaxis for 31–39 days. In RECORD2, patients undergoing THR received rivaroxaban for 31–39 days, or enoxaparin for 12±2 days followed by placebo up to 35 days. Patients undergoing TKR in RECORD3 and 4 received prophylaxis for 12±2 days. In all four trials the rivaroxaban regimens showed superior efficacy to the enoxaparin regimens with no significant increase in bleeding. The RECORD1–4 pooled analysis showed that rivaroxaban was significantly superior to enoxaparin for the primary endpoint, symptomatic VTE and all-cause mortality (0.8% vs 1.6%, respectively; p70–90, 〉90kg), gender, or renal function (CrCl 〉80, 50–80, 80 and 30 ml/min CrCl) groups studied. Similar trends were seen in the smaller subgroups of body weight extremes (〉110 kg subgroup - total VTE: 5/100 [5.0%] vs 8/119 [6.7%], respectively; ≤50 kg subgroup - any bleeding: 12/147 [8.2%] vs 8/162 [4.9%], respectively). These results suggest that age, body weight, gender and renal function (〉30 ml/min CrCl) have no clinically relevant effect on the efficacy or safety of rivaroxaban as thrombroprophylaxis following major orthopedic surgery. Subgroup Total VTE Odds ratio (rivaroxaban vs enoxaparin regimens) (95% CI Major VTE Odds ratio (rivaroxaban vs enoxaparin regimens) (95% CI) Any major or non-major bleeding Hazard ratio (rivaroxaban vs enoxaparin regimens) (95% CI) *Because of study exclusion criteria, few patients had CrCl 70–90kg 0.45 (0.34–0.59) 0.21 (0.11–0.39) 0.95 (0.77–1.17) 〉90kg 0.38 (0.25–0.57) 0.32 (0.13–0.69) 1.22 (0.95–1.58) Gender Male 0.35 (0.25–0.48) 0.21 (0.10–0.40) 1.12 (0.93–1.36) Female 0.47 (0.37–0.59) 0.27 (0.16–0.45) 1.06 (0.87–1.28) CrCl (ml/min) 〉80 0.35 (0.27–0.46) 0.22 (0.12–0.38) 1.12 (0.94–1.35) 50–80 0.60 (0.45–0.81) 0.30 (0.15–0.56) 0.99 (0.79–1.24)
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    Impaired response to GM-CSF and G-CSF, and enhanced apoptosis in C/EBPβ-deficient hematopoietic cells (2008)
    American Society of Hematology
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    Publication Date: 2008-03-15
    Description: Transcription factors known as CCAAT enhancer binding proteins (C/EBPs) are involved in hematopoietic differentiation, including myelopoiesis and granulopoiesis. C/EBPβ-deficient mice develop normally; however, they exhibit defective macrophage function, resulting in increased susceptibility to infection. Little is known about the role of C/EBPβ in granulopoiesis; therefore, we examined granulopoiesis in C/EBPβ-deficient mice. Morphology, the number of peripheral blood and bone marrow cells, and the expression of genes specific for the myeloid lineage were normal in C/EBPβ-deficient mice. Interestingly, the hematopoietic progenitor cells of C/EBPβ-deficient mice did not respond normally to granulocyte/macrophage-colony stimulating factor and granulocyte colony stimulating factor. In addition, C/EBPβ-deficient neutrophils displayed enhanced apoptosis compared with wild-type neutrophils. Our present results indicate that C/EBPβ helps regulate survival of neutrophils, downstream of the granulocyte colony stimulating factor receptor.
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    The Protein C Pathway in Human and Murine Sickle Cell Disease: Alterations in Protein C, Thrombomodulin (TM), and Endothelial Protein C Receptor (EPCR) at Baseline and during Acute Vaso-Occlusion (2008)
    American Society of Hematology
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    Publication Date: 2008-11-16
    Description: The coagulation system is activated in sickle cell disease (SCD) and acute vaso-occlusion may heighten hypercoagulability. Protein C, a natural anticoagulant, has been reported to be low in individuals with SCD. Therefore, the natural anticoagulation pathway may be disrupted in SCD. The objective of this study is to more fully evaluate the protein C pathway in murine and human SCD by examining levels of: coagulation activation; protein C activity; thrombomodulin (TM); and endothelial protein C receptor (EPCR). In order to assess the level of activation of the coagulation system, we measured plasma thrombin/antithrombin (TAT) complex levels in humans and mice. TAT levels were elevated in 22 humans with SCD versus 9 healthy controls at baseline, and levels increased further in 15 individuals with SCD during acute vaso-occlusive events (5.6±1.2 vs. 2.4±0.2 vs. 9.2±1.8ug/L respectively, p=0.02). In order to study acute vaso-occlusive events in mice, we developed a model of acute vaso-occlusion by exposing Berkeley SCD mice to 3 hours of hypoxia (FI02 8–10%) followed by 2, 4, or 21 hours of reoxygenation in room air (HR2, HR4, HR21). In support of our human findings, TAT was elevated in SCD mice compared to HbA mice at baseline, and increased further in SCD mice exposed to HR2 (n=5–14 per group, p
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    Autologous Stem Cell Transplantation after Myeloablative Therapy in First Remission May Be Beneficial in Patients with Advanced Stage Follicular Lymphoma after Front-Line Therapy with R-CHOP. An Analysis of Two Consecutive Studies of the German Low Grade Lymphoma Study Group (GLSG) (2008)
    American Society of Hematology
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    Publication Date: 2008-11-16
    Description: The addition of Rituximab (R) to front-line combination chemotherapy has substantially improved the long term perspectives of patients with advanced stage follicular lymphoma (FL) resulting in median progression free survival (PFS) times of more than 36 months. In this situation the potential role of myeloablative herapy with subsequent autologous stem cell transplantation (ASCT) in 1st remission needs to be critically reassessed. For this purpose two consecutive studies of the GLSG were analyzed both randomizing in 1st remission for Interferon alpha (IFN) maintenance therapy versus ASCT. In the GLSG trial ‘96 initial therapy comprised a randomized comparison of CHOP versus Mitoxantrone, Chlorambucil and Prednisone (MCP) (total patient number 312) while in GLSG study ‘00 CHOP was randomly compared to R-CHOP (total patient number 268). Hence, both studies had an identical treatment arm of CHOP followed by either IFN maintenance or ASCT. In both studies, the identical treatments revealed superimposable results with a 5 years PFS of 27% after CHOP and IFN maintenance and 66% after CHOP followed by ASCT. Taking these data as internal control R-CHOP followed by IFN maintenance achieved a 5 year PFS of 67% which is hence comparable to CHOP followed by ASCT. R-CHOP followed by ASCT, however, revealed a 5 year PFS of 79% with only one relapse after 24 months. Figure Figure Although the difference between R-CHOP followed by IFN maintenance or ASCT is currently not yet significant it strongly suggests a beneficial effect of ASCT in the era of R-CHOP front-line therapy particularly for intermediate of high risk patients with advanced stage FL.
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    Hemojuvelin regulates hepcidin expression via a selective subset of BMP ligands and receptors independently of neogenin (2008)
    American Society of Hematology
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    Publication Date: 2008-05-15
    Description: Hemojuvelin (HJV) is a coreceptor for bone morphogenetic protein (BMP) signaling that regulates hepcidin expression and iron metabolism. However, the precise combinations of BMP ligands and receptors used by HJV remain unknown. HJV has also been demonstrated to bind to neogenin, but it is not known whether this interaction has a role in regulating hepcidin expression. In the present study, we show that BMP-2, BMP-4, and BMP-6 are endogenous ligands for HJV in hepatoma-derived cell lines, and that all 3 of these ligands are expressed in human liver. We demonstrate in vitro that HJV selectively uses the BMP type II receptors ActRIIA and BMPRII, but not ActRIIB, and HJV enhances utilization of ActRIIA by BMP-2 and BMP-4. Interestingly, ActRIIA is the predominant BMP type II receptor expressed in human liver. While HJV can use all 3 BMP type I receptors (ALK2, ALK3, and ALK6) in vitro, only ALK2 and ALK3 are detected in human liver. Finally, we show that HJV-induced BMP signaling and hepcidin expression are not altered by neogenin overexpression or by inhibition of endogenous neogenin expression. Thus, HJV-mediated BMP signaling and hepcidin regulation occur via a distinct subset of BMP ligands and BMP receptors, independently of neogenin.
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    Myeloma-derived Dickkopf-1 disrupts Wnt-regulated osteoprotegerin and RANKL production by osteoblasts: a potential mechanism underlying osteolytic bone lesions in multiple myeloma (2008)
    American Society of Hematology
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    Publication Date: 2008-07-01
    Description: Multiple myeloma (MM) is characterized by osteolytic bone lesions (OBL) that arise as a consequence of osteoblast inactivation and osteoclast activation adjacent to tumor foci within bone. Wnt signaling in osteoblasts regulates osteoclastogenesis through the differential activation and inactivation of Receptor Activator of Nuclear factor Kappa B Ligand (RANKL) and osteoprotegerin (OPG), positive and negative regulators of osteoclast differentiation, respectively. We demonstrate here that MM cell–derived DKK1, a soluble inhibitor of canonical Wnt signaling, disrupted Wnt3a-regulated OPG and RANKL expression in osteoblasts. Confirmed in multiple independent assays, we show that pretreatment with rDKK1 completely abolished Wnt3a-induced OPG mRNA and protein production by mouse and human osteoblasts. In addition, we show that Wnt3a-induced OPG expression was diminished in osteoblasts cocultured with a DKK1-expressing MM cell line or primary MM cells. Finally, we show that bone marrow sera from 21 MM patients significantly suppressed Wnt3a-induced OPG expression and enhanced RANKL expression in osteoblasts in a DKK1-dependent manner. These results suggest that DKK1 may play a key role in the development of MM-associated OBL by directly interrupting Wnt-regulated differentiation of osteoblasts and indirectly increasing osteoclastogenesis via a DKK1-mediated increase in RANKL-to-OPG ratios.
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  • 89
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    Redistribution of accumulated cell iron: a modality of chelation with therapeutic implications (2008)
    American Society of Hematology
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    Publication Date: 2008-02-01
    Description: Various pathologies are characterized by the accumulation of toxic iron in cell compartments. In anemia of chronic disease, iron is withheld by macrophages, leaving extracellular fluids iron-depleted. In Friedreich ataxia, iron levels rise in the mitochondria of excitable cells but decrease in the cytosol. We explored the possibility of using deferiprone, a membrane-permeant iron chelator in clinical use, to capture labile iron accumulated in specific organelles of cardiomyocytes and macrophages and convey it to other locations for physiologic reuse. Deferiprone's capacity for shuttling iron between cellular organelles was assessed with organelle-targeted fluorescent iron sensors in conjunction with time-lapse fluorescence microscopy imaging. Deferiprone facilitated transfer of iron from extracellular media into nuclei and mitochondria, from nuclei to mitochondria, from endosomes to nuclei, and from intracellular compartments to extracellular apotransferrin. Furthermore, it mobilized iron from iron-loaded cells and donated it to preerythroid cells for hemoglobin synthesis, both in the presence and in the absence of transferrin. These unique properties of deferiprone underlie mechanistically its capacity to alleviate iron accumulation in dentate nuclei of Friedreich ataxia patients and to donate tissue-chelated iron to plasma transferrin in thalassemia intermedia patients. Deferiprone's shuttling properties could be exploited clinically for treating diseases involving regional iron accumulation.
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  • 90
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    Resistance of mature T cells to oncogene transformation (2008)
    American Society of Hematology
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    Publication Date: 2008-09-15
    Description: Leukemia caused by retroviral insertional mutagenesis after stem cell gene transfer has been reported in several experimental animals and in patients treated for X-linked severe combined immunodeficiency. Here, we analyzed whether gene transfer into mature T cells bears the same genotoxic risk. To address this issue in an experimental “worst case scenario,” we transduced mature T cells and hematopoietic progenitor cells from C57BL/6 (Ly5.1) donor mice with high copy numbers of gamma retroviral vectors encoding the potent T-cell oncogenes LMO2, TCL1, or ΔTrkA, a constitutively active mutant of TrkA. After transplantation into RAG-1–deficient recipients (Ly5.2), animals that received stem cell transplants developed T-cell lymphoma/leukemia for all investigated oncogenes with a characteristic phenotype and after characteristic latency periods. Ligation-mediated polymerase chain reaction analysis revealed monoclonality or oligoclonality of the malignancies. In striking contrast, none of the mice that received T-cell transplants transduced with the same vectors developed leukemia/lymphoma despite persistence of gene-modified cells. Thus, our data provide direct evidence that mature T cells are less prone to transformation than hematopoietic progenitor cells.
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  • 91
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    Prospective, multicenter randomized GITMO/IIL trial comparing intensive (R-HDS) versus conventional (CHOP-R) chemoimmunotherapy in high-risk follicular lymphoma at diagnosis: the superior disease control of R-HDS does not translate into an overall survival advantage (2008)
    American Society of Hematology
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    Publication Date: 2008-04-15
    Description: In this randomized multicenter study of 136 patients, 6 courses of CHOP (cyclo-phosphamide/doxorubicin/vincristine/prednisone) followed by rituximab (CHOP-R) were compared with rituximab-supplemented high-dose sequential chemotherapy with autografting (R-HDS) to assess the value of intensified chemo-therapy as a first-line treatment for high-risk follicular lymphoma (FL) after the introduction of monoclonal antibodies. The analysis was intention to treat with event-free survival (EFS) as the primary endpoint. Complete remission (CR) was 62% with CHOP-R and 85% with R-HDS (P 〈 .001). At a median follow-up (MFU) of 51 months, the 4-year EFS was 28% and 61%, respectively (P 〈 .001), with no difference in overall survival (OS). Molecular remission (MR) was achieved in 44% of CHOP-R and 80% of R-HDS patients (P 〈 .001), and was the strongest independent outcome predictor. Patients relapsing after CHOP-R underwent salvage R-HDS in 71% of cases. Salvage R-HDS had an 85% CR rate and a 68% 3-year EFS (MFU, 30 months). We conclude that (1) achieving MR is critical for effective disease control, regardless of which treatment is used; (2) R-HDS ensures superior disease control and molecular outcome than CHOP-R, but no OS improvement; and (3) CHOP-R failures have a good outcome after salvage R-HDS, suggesting that relapsed/refractory FL could be the most appropriate setting for R-HDS–like treatments. This trial was registered at www.clinicaltrials.gov as no. NCT00435955.
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    Distinct functional significance of Akt and mTOR constitutive activation in mantle cell lymphoma (2008)
    American Society of Hematology
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    Publication Date: 2008-05-15
    Description: Functional characterization of signaling pathways that critically control mantle cell lymphoma (MCL) cell growth and survival is relevant to designing new therapies for this lymphoma. We herein demonstrate that the constitutive activation of Akt correlates with the expression of the phosphorylated, inactive form of PTEN. Phosphatidyl-inositol-3 kinase (PI3-K)/Akt or mammalian target of rapamycin (mTOR) inhibition decreased the growth of both primary MCL cultures and established cell lines and antagonizes the growth-promoting activity of CD40 triggering and IL-4. These effects are mediated by nuclear accumulation of the p27Kip1 inhibitor induced by down-regulation of the p45Skp2 and Cks1 proteins, which target p27Kip1 for degradation. Moreover, Akt inhibition down-regulated cyclin D1 by promoting its proteasome-dependent degradation driven by GSK-3. Intriguingly, mTOR inhibition affected cyclin D1 proteolysis only in MCL cells in which GSK-3 is under the direct control of mTOR, suggesting that different MCL subsets could be differently responsive to mTOR inhibition. Finally, PI3-K/Akt inhibitors, but not rapamycin, induced variable levels of caspase-dependent apoptosis and reduced telomerase activity. These results indicate that Akt and mTOR activation have distinct functional relevance in MCL and suggest that targeting Akt may result in more effective therapeutic effects compared with mTOR inhibition.
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    Implications for the Use of Monoclonal Antibodies in Future Adult ALL Trials: Analysis of Antigen Expression in 505 B-Lineage (B-Lin) ALL Patients (pts) on the MRC UKALLXII/ECOG2993 Intergroup Trial. (2008)
    American Society of Hematology
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    Publication Date: 2008-11-16
    Description: MRC UKALLXII/ECOG2993 accrued 739 ECOG pts over 13 years. ECOG’s reference laboratories centrally characterized 613 (91%) and 505 were B-Lin ALLs. Expression of 32 antigens (Ags), including 9 myeloid-associated Ags, was determined by multiparameter flow cytometry on gated blasts, both as percentage of Ag expressing blasts and intensity of antibody staining (equivalent of Ag density). To test for the potential therapeutic efficacy of monoclonal antibodies, such as rituximab, epratuzumab, alemtuzumab, or gemtuzumab in future trials, expression of Ags for these antibodies (CD20, CD22, CD52, or CD33, respectively) was determined. In E2993, 14% of pts typed as Pro-B (CD10 negative), 71% as Early Pre-B (CD10 positive), 13% as Pre-B (intracytoplasmic mu positive), and 2% as Mature B-ALL (surface mu chains positive). CD20 expression correlated with the stage of B-lymphoid maturation (p=5.4E-13) (see table). Median CD20 intensity of fluorescence was lowest in Pro-B and highest in Mature B-ALL. Membrane expression of CD22 was lower in Pro-B compared with the other three groups, Early Pre-B, Pre-B and Mature B (p=1.0E-5) but indistinguishable among the latter three (p=0.21). While levels of CD20 and CD22 had no effect on complete remission (CR) and overall survival (OS) univariatly, higher CD22 expression was significantly correlated with better OS (p=0.02) in a bivariate Cox model of CD20 and CD22. With respect to myeloid Ags, CD33/CD13 expression was associated with Early Pre-B (p=0.02), and CD65(s)/CD15(s) with Pro-B ALL (p
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    Oral Eltrombopag for the Long-Term Treatment of Patients with Chronic Idiopathic Thrombocytopenic Purpura: Results of a Phase III, Double- Blind, Placebo-Controlled Study (RAISE) (2008)
    American Society of Hematology
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    Publication Date: 2008-11-16
    Description: INTRODUCTION: Eltrombopag (PROMACTA®/REVOLADE®; GlaxoSmithKline, Collegeville, PA, USA) is a first-in-class, oral, small molecule, non-peptide, thrombopoietin receptor agonist being studied for the treatment of thrombocytopenia related to a variety of conditions. METHODS: RAISE was a 6-month, randomized, double-blind, placebo-controlled, phase III study that evaluated the efficacy and safety of eltrombopag in previously treated adults with chronic idiopathic thrombocytopenic purpura (ITP) with platelet counts 15% had received at least 3 prior ITP medications. Patients who received eltrombopag were 8 times more likely to achieve platelet counts 50,000 to 400,000/μL during the 6-month treatment period compared with patients on placebo (OR [95% CI] = 8.2 [4.32, 15.38]; P
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    Molecular profiling of LGL leukemia reveals role of sphingolipid signaling in survival of cytotoxic lymphocytes (2008)
    American Society of Hematology
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    Publication Date: 2008-08-01
    Description: T-cell large granular lymphocyte (LGL) leukemia is characterized by clonal expansion of CD3+CD8+ cells. Leukemic LGLs correspond to terminally differentiated effector-memory cytotoxic T lymphocytes (CTLs) that escape Fas-mediated activation-induced cell death (AICD) in vivo. The gene expression signature of peripheral blood mononuclear cells from 30 LGL leukemia patients showed profound dysregulation of expression of apoptotic genes and suggested uncoupling of activation and apoptotic pathways as a mechanism for failure of AICD in leukemic LGLs. Pathway-based microarray analysis indicated that balance of proapoptotic and antiapoptotic sphingolipid-mediated signaling was deregulated in leukemic LGLs. We further investigated sphingolipid pathways and found that acid ceramidase was constitutively overexpressed in leukemic LGLs and that its inhibition induced apoptosis of leukemic LGLs. We also showed that S1P5 is the predominant S1P receptor in leukemic LGLs, whereas S1P1 is down-regulated. FTY720, a functional antagonist of S1P-mediated signaling, induced apoptosis in leukemic LGLs and also sensitized leukemic LGLs to Fas-mediated death. Collectively, these results show a role for sphingolipid-mediated signaling as a mechanism for long-term survival of CTLs. Therapeutic targeting of this pathway, such as use of FTY720, may have efficacy in LGL leukemia.
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  • 96
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    CD300a/c regulate type I interferon and TNF-α secretion by human plasmacytoid dendritic cells stimulated with TLR7 and TLR9 ligands (2008)
    American Society of Hematology
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    Publication Date: 2008-08-15
    Description: Activation of human plasmacytoid dendritic cells (pDCs) with ligands for Toll-like receptors (TLRs) 7 and 9 induces the secretion of type I interferons and other inflammatory cytokines as well as pDC differentiation. Transcripts for 2 members of the CD300 gene family, CD300a and CD300c, were identified on pDCs during gene expression studies to identify new immunoregulatory molecules on pDCs. We therefore investigated the expression of CD300a and CD300c and their potential regulation of pDC function. CD300a/c RNA and surface expression were downregulated after stimulation of pDCs with TLR7 and TLR9 ligands. Exogenous interferon (IFN)-α down-regulated CD300a/c expression, whereas neutralizing IFN-α abolished TLR ligand–induced CD300a/c down-regulation. This implicates IFN-α in regulating CD300a/c expression in pDCs. In addition, IFN-α favored tumor necrosis factor (TNF)-α secretion by CpG-induced pDCs. CD300a/c triggering by cross-linking antibody reduced TNF-α and increased IFN-α secretion by pDCs. Furthermore, CD300a/c triggering, in the presence of neutralizing IFN-α, further reduced TNF-α secretion. These data indicate that CD300a and CD300c play an important role in the cross-regulation of TNF-α and IFN-α secretion from pDCs.
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    A critical role for Lyn in acute myeloid leukemia (2008)
    American Society of Hematology
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    Publication Date: 2008-02-15
    Description: Receptor or nonreceptor tyrosine kinases (TKs) are known to play an important role in leukemogenesis. Here we studied the level of protein tyrosine phosphorylations in a series of fresh AML samples and evaluated the effect of TK inhibitors. Compared with normal hematopoietic progenitors, a high level of tyrosine phosphorylation was detected in most acute myeloid leukemia (AML) samples. The Src family kinases (SFKs) appeared constitutively activated in most cases, including in the CD34+CD38−CD123+ compartment as revealed by the level of phosphorylated tyrosine 416. Lyn was the major SFK family member expressed in an active form in AML cells where it was abnormally distributed throughout the plasma membrane and the cytosol as opposed to normal hematopoietic progenitors. The SFK inhibitor, PP2, strongly reduced the global level of tyrosine phosphorylations, inhibited cell proliferation, and induced apoptosis in patient samples without affecting normal granulomonocytic colony forming units. Moreover, silencing Lyn expression by small interfering RNA in primary AML cells strongly inhibited proliferation. Interestingly, a link between Lyn and the mTOR pathway was observed as PP2 and a Lyn knockdown both affected the phosphorylation of mTOR targets without inhibiting Akt phosphorylation. Lyn should be considered as a novel pharmacologic target for AML therapy.
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    Rituximab Maintenance Treatment of Relapsed/Resistant Follicular Non- Hodgkin’s Lymphoma: Long-Term Outcome of the EORTC 20981 Phase III Randomized Intergroup Study (2008)
    American Society of Hematology
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    Publication Date: 2008-11-16
    Description: Background. In 2005 we analyzed the results of a prospective randomized phase III intergroup trial evaluating the role of rituximab (R) both in remission induction and maintenance treatment of 465 relapsed/resistant follicular lymphoma (FL) patients. Major conclusions were that addition of R to CHOP induction yielded an increased ORR and CR rate, and that R maintenance strongly improved median progression free survival (PFS), both after induction with CHOP and R-CHOP, and overall survival (OS (van Oers et al Blood2006;108:3295). At that time the median follow for the maintenance phase was 33 months. Now we report the long-term outcome of maintenance treatment, with a median follow up of 6 years from start of maintenance. Study design. Patients with stages III or IV FL at initial diagnosis and relapsed after or resistant to a maximum of two non-anthracycline containing systemic chemotherapy regimens, were randomized to remission induction with either 6 cycles of standard CHOP (once every 3 weeks) or CHOP + R (375 mg/m2 at day 1 of each cycle of CHOP). Those with a complete or partial remission after 6 cycles of therapy underwent a second randomization to no further treatment (observation) or maintenance treatment with R (375 mg/m2 once every 3 months) until relapse or for a maximum period of two years. Results. 465 patients were randomized to induction with either CHOP (231) or R-CHOP (234). As reported, CHOP and R-CHOP induction yielded similar partial response rates (57% vs.56%), but significantly different CR rates (16% and 29%; p=0.0001). 334 patients were randomized to either R maintenance treatment (167) or observation (167). R maintenance resulted in a highly significant improvement of PFS: median 3.7 years versus 1.3 years in the observation arm (p
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  • 99
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    Lnk Controls Hematopoietic Stem Cell Self-Renewal through Direct Interactions with JAK2 and Contributes to Oncogenic JAK2-Induced Myeloproliferative Diseases in Mice (2008)
    American Society of Hematology
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    Publication Date: 2008-11-16
    Description: Hematopoietic stem cell (HSC) homeostasis and self-renewal are regulated by intrinsic cytokine signaling pathways. One important signaling axis for HSC is the cell surface receptor, Mpl, and its ligand, thrombopoietin (Tpo). Upon Tpo stimulation, Mpl activates Janus Kinase (JAK2) that triggers a cascade of downstream signal transduction pathways that regulates many aspects of cell development. Under steady-state conditions, mice lacking the inhibitory adaptor protein Lnk harbor an expanded HSC pool with enhanced self-renewal. Surprisingly, we found that Lnk−/− HSCs have an increased quiescent fraction, decelerated cell cycle kinetics, and enhanced resistance to repeated 5-Florouracil (5-FU) treatments in vivo compared to wild type HSCs. We further provided genetic evidence demonstrating that Lnk controls HSC quiescence and self-renewal predominantly through Mpl. Consistent with this observation, Lnk deficiency in HSCs potentiates JAK2 activation in response to TPO. Biochemical experiments reveal that Lnk directly binds to phosphorylated tyrosine residues in JAK2 following TPO stimulation. Dysregulation of cytokine receptor signaling pathways leads to hematological malignancies. Abnormal activation of JAK2 by a chromosomal translocation between the transcription factor Tel and JAK2 (Tel/JAK2) was shown to cause atypical Chronic Myelogenous Leukemia (aCML). Recently, the JAK2 V617F mutation has been observed at high frequencies in several myeloproliferative diseases (MPDs). The JAK2V617F mutant retains Lnk binding ability, suggesting Lnk status could modify MPD development. Indeed, we found that loss of Lnk accelerates oncogenic JAK2- induced CML/MPD in the mouse transplant models. Therefore, we identified Lnk as a physiological negative regulator of JAK2 in stem cells that may contribute to leukemic transformation conferred by oncogenic JAK2.
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    The SH2-B Adaptor Protein Negatively Regulates EPO-Dependent Signalling Via Interaction with Erythropoietin Receptor Ptyr-343 (2008)
    American Society of Hematology
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    Publication Date: 2008-11-16
    Description: Erythropoiesis is a developmentally important process, whereby multipotent hematopoietic stem cells differentiate into mature erythrocytes. Erythropoietin (EPO) is a critical regulator in this process and mediates its signal via the erythropoietin receptor (EPO-R) and the primary associated tyrosine kinase, JAK2. EPO, EPO-R and JAK2 play a crucial role in erythropoiesis, as deficiency in any of these proteins results in an embryonic lethal anemia. Structural-functional studies and murine knock-in models have shown EPO-R pTyr-343 to play a critical role in EPO mediated signalling. STAT-5 is activated by EPO-R pTyr-343, but STAT5ΔN mice do not have any profound erythroid abnormalities. Such evidence has led our group to hypothesize that other SH2 containing effectors interact with EPO-R pTyr-343. Cloning of Ligand Target screening was utilized to demonstrate that EPO-R pTyr-343 binds to adaptor protein SH2-Bβ. SH2-B contains multiple protein-protein interaction domains including multiple proline-rich regions, a PH domain and an SH2 domain. Although SH2-B does play a role in a number of signaling pathways, it is not required for embryonic development. Since SH2-B is a potent regulator of JAK2 in context of Growth Hormone and Leptin signaling, and it can directly interact with EPO-R pTyr-343, we hypothesize that SH2-B functions as an important adaptor protein downstream of the EPO-R.H2-B constitutively associates to the inactive EPO-R, an interaction that is independent of JAK2 binding to the EPO-R. Upon EPO stimulation, enhanced SH2-dependent binding of SH2-B to pTyr-343 and pTyr-401 of the EPO-R was confirmed utilizing a panel of EPO-R truncation mutants. The EPO mediated interaction between SH2-B and activated EPO-R is both dose and time dependent. EPO stimulation also results in SH2-B serine and threonine phosphorylation. Importantly, the interaction of SH2-B and EPO-R was observed in erythroid cell lines and primary murine splenocytes. The function of SH2-B in EPO signaling was investigated via knocking down SH2-B in Ba/F3-EPO-R cells. Knock down of SH2-B results in hypersensitive EPO-dependent phosphorylation of multiple targets including the EPO-R, JAK2, STAT5 and Erk1/2. It is evident that SH2-B is a global negative regulator of EPO-dependent signaling via its ability to affect EPO-dependent JAK2 activation.
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