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  • 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring  (23)
  • Springer-Verlag  (12)
  • Springer  (11)
  • American Institute of Physics (AIP)
  • 2005-2009  (23)
  • 1950-1954
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Years
Year
  • 1
    Publication Date: 2017-04-04
    Description: Dikes within stratovolcanoes are commonly expected to have radial patterns. However, other patterns may also be found, due to regional stresses, magmatic reservoirs and topographic variations. Here, we investigate dike patterns within volcanic edifices by studying dike and fissure complexes at Somma-Vesuvius and Etna (Italy) using analogue models. At the surface, the dikes and fissures show a radial configuration. At depths of tens to several hundreds of metres, in areas exposed by erosion, tangential and oblique dikes are also present. Analogue models indicate that dikes approaching the flanks of cones, regardless of their initial orientation, reorient to become radial (parallel to the maximum gravitational stress). This re-orientation is a significant process in shallow magma migration and may also control the emplacement of dikefed fissures reaching the lower slopes of the volcano.
    Description: This work was partly financed with DPC-INGV LAVA Project.
    Description: Published
    Description: 219-223
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.2. Tettonica attiva
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: Dike propagation ; Central volcanic edifices ; Stress ; 04. Solid Earth::04.01. Earth Interior::04.01.03. Mantle and Core dynamics ; 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::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 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::04.08.02. Experimental volcanism ; 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 ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
    Publication Date: 2017-04-04
    Description: Large variations of the CO2 flux through the soil were observed between November 2002 and January 2006 at Mt. Etna volcano. In many cases, the CO2 flux was strongly influenced by changes in air temperature and atmospheric pressure. A new filtering method was then developed to remove the atmospheric influences on soil CO2 flux and, at the same time, to highlight the variations strictly related to volcanic activity. Successively, the CO2 corrected data were quantitatively compared with the spectral amplitude of the volcanic tremor by cross correlation function, cross-wavelet spectrum and wavelet coherence. These analyses suggested that the soil CO2 flux variations preceded those of volcanic tremor by about 50 days. Given that volcanic tremor is linked to the shallow (a few kilometer) magma dynamics and soil CO2 flux related to the deeper (*12 km b.s.l.) magma dynamics, the “delayed similarity” between the CO2 flux and the volcanic tremor amplitude was used to assess the average speed in the magma uprising into the crust, as about 170–260 m per day. Finally, the large amount of CO2 released before the onset of the 2004–2005 eruption indicated a deep ingression of new magma, which might have triggered such an eruption.
    Description: In press
    Description: N/A or not JCR
    Description: reserved
    Keywords: Mt. Etna ; Soil CO2 flux ; Volcanic tremor ; Cross-wavelet spectrum ; Wavelet coherence ; Cross correlation function ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data ; 05. General::05.02. Data dissemination::05.02.02. Seismological data
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 3
    Publication Date: 2017-04-04
    Description: Carbon dioxide flux from the soil is regularly monitored in selected areas of Vesuvio and Solfatara (Campi Flegrei, Pozzuoli) with the twofold aim of i) monitoring spatial and temporal variations of the degassing process and ii) investigating if the surface phenomena could provide information about the processes occurring at depth. At present, the surveyed areas include 15 fixed points around the rim of Vesuvio and 71 fixed points in the floor of Solfatara crater. Soil CO2 flux is measured since 1998, at least once a month, in both areas. In addition, two automatic permanent stations, located at Vesuvio and Solfatara, measure the CO2 flux and some environmental parameters that can potentially influence the CO2 diffuse degassing. Series acquired by continuous stations are characterized by an annual periodicity that is related to the typical periodicities of some meteorological parameters. Conversely, series of CO2 flux data arising from periodic measurements over the arrays of Vesuvio and Solfatara, are less dependent on external factors such as meteorological parameters, local soil properties (porosity, hydraulic conductivity) and topographic effects (high or low ground). Therefore we argue that the long-term trend of this signal contains the “best” possible representation of the endogenous signal related to the upflow of deep hydrothermal fluids.
    Description: In press
    Description: on line first
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: CO2 degassing ; volcanic monitoring ; Solfatara ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 4
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    Springer-Verlag
    Publication Date: 2017-04-04
    Description: The July-August 2001 eruption of Mt. Etna stimulated widespread public and media interest, caused significant damage to tourist facilities, and for several days threatened the town of Nicolosi on the S flank of the volcano. Seven eruptive fissures were active, five on the S flank between 3050 and 2100 m altitude, and two on the NE flank between 3080 and 2600 m elevation. All produced lava flows over various periods during the eruption, the most voluminous of which reached a length of 6.9 km. Mineralogically the 2001 lavas fall into two distinct groups, indicating that magma was supplied through two different and largely independent pathways, one extending laterally from the central conduit system through radial fissures, the other being a vertically ascending eccentric dike. Furthermore one of the eccentric vents, at 2570 m elevation, was the site of vigorous phreatomagmatic activity as the dike cut through a shallow aquifer, both during the intial and closing stages of the eruption. For six days the magma column feeding this vent was more or less effectively sealed from the aquifer, permitting powerful explosive and effusive magmatic activity. While the eruption was characterized by a highly dynamic evolution, complex interactions between some of the eruptive fissures, and changing eruptive styles, its total volume (~25 x 106 m3 of lava and 5-10 x 106 m3 of pyroclastics) was relatively small in comparison with other recent eruptions of Etna. Effusion rates were calculated on a daily basis and reached peaks of 14-16 m3 s-1 while the average effusion rate at all fissures was about 11 m3 s-1, which is not exceptionally high. The eruption showed a number of peculiar features, but none of these (except the contemporaneous lateral and eccentric activity) represented a significant deviation from Etna's eruptive behavior in the long term. However, the 2001 eruption could be but the first in a series of flank eruptions, some of which might be more voluminous and hazardous. Placed in a long-term context, the eruption confirms a distinct trend, initiated during the past 50 years, toward higher production rates and more frequent eruptions, which might bring Etna back to similar levels of activity as during the early to mid 17th century.
    Description: Published
    Description: 461-476
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    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: Mt. Etna ; 2001 eruption ; Lava flow-field evolution ; Central-lateral vs. eccentric activity ; Phreatomagmatism ; Eruption dynamics ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 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::04.08.01. Gases ; 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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 5
    Publication Date: 2017-04-04
    Description: Most flank eruptions within a central stratovolcano are triggered by lateral draining of magma from its central conduit, and only few eruptions appear to be independent of the central conduit. In order to better highlight the dynamics of flank eruptions in a central stratovolcano, we review the eruptive history of Etna over the last 100 years. In particular, we take into consideration the Mount Etna eruption in 2001, which showed both summit activity and a flank eruption interpreted to be independent from the summit system. The eruption started with the emplacement of a ~N-S trending peripheral dike, responsible for the extrusion of 75% of the total volume of the erupted products. The rest of the magma was extruded through the summit conduit system (SE crater), feeding two radial dikes. The distribution of the seismicity and structures related to the propagation of the peripheral dike and volumetric considerations on the erupted magmas exclude a shallow connection between the summit and the peripheral magmatic systems during the eruption. Even though the summit and the peripheral magmatic systems were independent at shallow depths (〈3 km b.s.l.), petro-chemical data suggest that a common magma rising from depth fed the two systems. This deep connection resulted in the extrusion of residual magma from the summit system and of new magma from the peripheral system. Gravitational stresses predominate at the surface, controlling the emplacement of the dikes radiating from the summit; conversely, regional tectonics, possibly related to N-S trending structures, remains the most likely factor to have controlled at depth the rise of magma feeding the peripheral eruption.
    Description: Published
    Description: 517-529
    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: Central volcanoes ; Summit and flank eruptions ; Dikes ; Tectonics ; Volcano load ; Mount Etna ; 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::04.07. 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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 6
    Publication Date: 2017-04-04
    Description: High precision aerial photogrammetry has been used in addition to other geophysical techniques such as bathymetric surveys, geodetic measurements, microseismicity recording, etc., for monitoring slope deformations and the volcanic activity of Stromboli Island (Aeolian Arc, Italy), during the last effusive eruption, which started on December 28, 2002 and soon after the major landslide/ tsunami event of December 30. Qualitative and quantitative description of topographic and morphological changes of the Sciara del Fuoco were possible thanks to a recent preeruption photogrammetric survey performed in 2001; the comparisons of 12 multi-temporal digital terrain models carried out during the period January–June 2003 were used to evaluate the displaced mass by the landslide, the lava accumulation and the erosion processes of the Sciara del Fuoco. After the end of the eruption, four additional photogrammetric surveys were performed between July 2003 and October 2005 to monitor the evolution of the slope and detect potential instability phenomena. The slope appeared significantly modified and continued to evolve, showing marked erosion both on the lower part and toward the craters terrace. Over the same period, the new lava flows showed progressive contraction of the thicker part of the lava pile caused by its cooling and compaction and the possible sliding along the shear surface of the December 2002 deep-seated movement. The present morphology seems to be far from equilibrium and the deformation processes are still ongoing, justifying a continuous monitoring activity to understand the evolution of these instability phenomena.
    Description: Dipartimento della Protezione Civile (DPC) and Istituto Nazionale di Geofisica e Vulcanologia (INGV), Project V1_2
    Description: Published
    Description: 703–715
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: reserved
    Keywords: Stromboli ; Sciara del Fuoco ; Digital photogrammetry ; Digital terrain models ; Morphology ; Landslide ; Slope deformation ; 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
    Publication Date: 2017-04-04
    Description: Abstract After 16 months of quiescence, Mount Etna began to erupt again in mid-July 2006. The activity was concentrated at and around the Southeast Crater (SEC), one of the four craters on the summit of Etna, and eruptive activity continued intermittently for 5 months. During this period, numerous vents displayed a wide range of eruptive styles at different times. Virtually all explosive activities took place at vents at the summit of the SEC and on its flanks. Eruptive episodes, which lasted from 1 day to 2 weeks, became shorter and more violent with time. Volcanic activity at these vents was often accompanied by dramatic mass-wasting processes such as collapse of parts of the cone, highly unusual flowage processes involving both old rocks and fresh magmatic material, and magma– water interaction. The most dramatic events took place on 16 November, when numerous rockfalls and pyroclastic density currents (PDCs) were generated during the opening of a large fracture on the SE flank of the SEC cone. The largest PDCs were clearly triggered explosively, and there is evidence that much of the energy was generated during the interaction of intruding magma with wet rocks on the cone’s flanks. The most mobile PDCs traveled up to 1 km from their source. This previously unknown process on Etna may not be unique on this volcano and is likely to have taken place on other volcanoes. It represents a newly recognized hazard to those who visit and work in the vicinity of the summit of Etna.
    Description: A part of this research was funded by the Istituto Nazionale di Geofisica e Vulcanologia (INGV) and by the Dipartimento per la Protezione Civile (Italy).
    Description: Published
    Description: 1249–1268
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: open
    Keywords: Mount Etna ; Pyroclastic density currents ; Lava–water interaction ; Hydrothermal alteration ; Hazards ; Volcano instability ; 2006 eruption ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 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::05.08. Risk::05.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 8
    Publication Date: 2017-04-04
    Description: This study presents baseline data for future geochemical monitoring of the active Tacaná volcano–hydrothermal system (Mexico–Guatemala). Seven groups of thermal springs, related to a NW/SE-oriented fault scarp cutting the summit area (4,100m a.s.l.), discharge at the northwest foot of the volcano (1,500–2,000m a.s.l.); another one on the southern ends of Tacaná (La Calera). The near-neutral (pH from 5.8 to 6.9) thermal (T from 25.7°C to 63.0°C) HCO3–SO4 waters are thought to have formed by the absorption of a H2S/SO2–CO2-enriched steam into a Cl-rich geothermal aquifer, afterwards mixed by Na/HCO3-enriched meteoric waters originating from the higher elevations of the volcano as stated by the isotopic composition (δD and δ18O) of meteoric and spring waters. Boiling temperature fumaroles (89°C at~3,600m a.s.l. NW of the summit), formed after the May 1986 phreatic explosion, emit isotopically light vapour (δD and δ18O as low as −128 and −19.9‰, respectively) resulting from steam separation from the summit aquifer. Fumarolic as well as bubbling gases at five springs are CO2-dominated. The δ13CCO2 for all gases show typical magmatic values of −3.6 ± 1.3‰ vs V-PDB. The large range in 3He/4He ratios for bubbling, dissolved and fumarolic gases [from 1.3 to 6.9 atmospheric 3He/4He ratio (RA)] is ascribed to a different degree of near-surface boiling processes inside a heterogeneous aquifer at the contact between the volcanic edifice and the crystalline basement (4He source). Tacaná volcano offers a unique opportunity to give insight into shallow hydrothermal and deep magmatic processes affecting the CO2/3He ratio of gases: bubbling springs with lower gas/water ratios show higher 3He/4He ratios and consequently lower CO2/3He ratios (e.g. Zarco spring). Typical Central American CO2/3He and 3He/4He ratios are found for the fumarolic Agua Caliente and Zarco gases (3.1 ± 1.6 × 1010 and 6.0 ± 0.9 RA, respectively). The L/S (5.9 ± 0.5)and (L + S)/M ratios (9.2 ± 0.7) for the same gases are almost identical to the ones calculated for gases in El Salvador, suggesting an enhanced slab contribution as far as the northern extreme of the Central American Volcanic Arc,Tacana
    Description: In press
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: JCR Journal
    Description: reserved
    Keywords: Tacaná volcano ; Fluid geochemistry ; Volcano–hydrothermal system ; Bubbling gases ; Fumaroles ; Isotopes ; Volcanic surveillance ; 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 ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 9
    Publication Date: 2017-04-04
    Description: Measurement of effusion rate is a primary objective for studies that model lava flow and magma system dynamics, as well as for monitoring efforts during on-going eruptions. However, its exact definition remains a source of confusion, and problems occur when comparing volume flux values that are averaged over different time periods or spatial scales, or measured using different approaches. Thus our aims are to: (1) define effusion rate terminology; and (2) assess the various measurement methods and their results. We first distinguish between instantaneous effusion rate, and time-averaged discharge rate. Eruption rate is next defined as the total volume of lava emplaced since the beginning of the eruption divided by the time since the eruption began. The ultimate extension of this is mean output rate, this being the final volume of erupted lava divided by total eruption duration. Whether these values are total values, i.e. the flux feeding all flow units across the entire flow field, or local, i.e. the flux feeding a single active unit within a flow field across which many units are active, also needs to be specified. No approach is without its problems, and all can have large error (up to ∼50%). However, good agreement between diverse approaches shows that reliable estimates can be made if each approach is applied carefully and takes into account the caveats we detail here. There are three important factors to consider and state when measuring, giving or using an effusion rate. First, the time-period over which the value was averaged; second, whether the measurement applies to the entire active flow field, or a single lava flow within that field; and third, the measurement technique and its accompanying assumptions.
    Description: Published
    Description: 1-22
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: reserved
    Keywords: Lava ; Instantaneous effusion rate ; Time-averaged discharge rate ; Eruption rate ; Monitoring ; 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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
    Publication Date: 2017-04-03
    Description: Soil-temperature measurements can provide information on the distribution of degassing fissures, their relationship to the internal structure of the volcano, and the temporal evolution of the system. At Vulcano Island (Italy) heat flux from a 〈3 km-deep magma body drives a hydrothermal system which extends across the main Fossa crater. This heat flux is also associated with variable magmatic gas flow. A high density map of soil-temperatures was made in 1996 at a constant depth of 30 cm on the central and southern inner flanks of the Fossa crater. These measurements extended over an area covering about 0.04 km2, across which the heat flux is predominantly associated with a shallow boiling aquifer. The map shows that hot zones relate to structures of higher permeability, mainly associated with a fissure system dating from the last eruptive cycle (1888-90). From 1996 to January 2005, we studied the evolution of the heat flux for the high temperature part of the map, both by repeating our measurements as part of fourteen visits, during which temperatures were measured at a constant depth, and using data from permanent stations which allowed soil-temperatures to be continuously measured for selected vertical profiles. These data allowed us to calculate the heat flux, and its variation, with good precision for values lower than about 100 W m-2, which is generally the case in the study area. Above 100 W m-2 although the heat flux value is underestimated its variations are recorded with an error less than 10%. During the period 1996-2004 two increases in the thermal flux were recorded. The first one was related to the seismic crisis of November 1998 which opened existing or new fissures. The second, in November 2004, was probably due to magma migration, and was associated with minor seismic activity.
    Description: Published
    Description: on line first
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: partially_open
    Keywords: hydrothermal flux ; soil temperature ; monitoring ; seismic activity ; Vulcano ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 11
    Publication Date: 2017-04-04
    Description: Between 1971 and 2001, the Southeast Crater was the most productive of the four summit craters of Mount Etna, with activity that can be compared, on a global scale, to the opening phases of the Pu‘u ‘Ō‘ō-Kūpaianaha eruption of Kīlauea volcano, Hawai‘i. The period of highest eruptive rate was between 1996 and 2001, when near-continuous activity occurred in five phases. These were characterized by a wide range of eruptive styles and intensities from quiet, non-explosive lava emission to brief, violent lava-fountaining episodes. Much of the cone growth occurred during these fountaining episodes, totaling 105 events. Many showed complex dynamics such as different eruptive styles at multiple vents, and resulted in the growth of minor edifices on the flanks of the Southeast Crater cone. Small pyroclastic flows were produced during some of the eruptive episodes, when oblique tephra jets showered the steep flanks of the cone with hot bombs and scoriae. Fluctuations in the eruptive style and eruption rates were controlled by a complex interplay between changes in the conduit geometry (including the growth of a shallow magma reservoir under the Southeast Crater), magma supply rates, and flank instability. During this period, volume calculations were made with the aid of GIS and image analysis of video footage obtained by a monitoring telecamera. Between 1996 and 2001, the bulk volume of the cone increased by ~36×106 m3, giving a total (1971– 2001) volume of ~72×106 m3. At the same time, the cone gained ~105 m in height, reaching an elevation of about 3,300 m. The total DRE volume of the 1996–2001 products was ~90×106m3. This mostly comprised lava flows (72×106 m3) erupted at the summit and onto the flanks of the cone. These values indicate that the productivity of the Southeast Crater increased fourfold during 1996–2001 with respect to the previous 25 years, coinciding with a general increase in the eruptive output rates and eruption intensity at Etna. This phase of intense summit activity has been followed, since the summer of 2001, by a period of increased structural instability of the volcano, marked by a series of important flank eruptions.
    Description: Published
    Description: 149-173
    Description: reserved
    Keywords: Mount Etna ; Lava fountaining ; Microplinian ; Remote video monitoring ; Volume calculations ; Cone growth ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 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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  • 12
    Publication Date: 2017-04-04
    Description: On 22 September 2002, 1 month before the beginning of the flank eruption on the NE Rift, an M-3.7 earthquake struck the northeastern part of Mt. Etna, on the westernmost part of the Pernicana fault. In order to investigate the ground deformation pattern associated with this event, a multi-disciplinary approach is presented here. Just after the earthquake, specific GPS surveys were carried out on two small sub-networks, aimed at monitoring the eastern part of the Pernicana fault, and some baselines belonging to the northeastern EDM monitoring network of Mt. Etna were measured. The leveling route on the northeastern flank of the volcano was also surveyed. Furthermore, an investigation using SAR interferometry was performed and also the continuous tilt data recorded at a high precision sensor close to the epicenter were analyzed to constrain the coseismic deformation. The results of the geodetic surveys show a ground deformation pattern that affects the entire northeastern flank of the volcano, clearly shaped by the Pernicana fault, but too strong and wide to be related only to an M-3.7 earthquake. Leveling and DInSAR data highlight a local strong subsidence, up to 7 cm, close to the Pernicana fault. Significant displacements, up to 2 cm, were also detected on the upper part of the NE Rift and in the summit craters area, while the displacements decrease at lower altitude, suggesting that the dislocation did not continue further eastward. Three-dimensional GPS data inversions have been attempted in order to model the ground deformation source and its relationship with the volcano plumbing system. The model has also been constrained by vertical displacements measured by the leveling survey and by the deformation map obtained by SAR interferometry.
    Description: Published
    Description: 757-768
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: partially_open
    Keywords: Ground deformation ; Modeling ; Flank dynamics ; Volcano-tectonics ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 13
    Publication Date: 2017-04-04
    Description: An open channel lava flow on Mt. Etna (Sicily) was observed during May 30–31, 2001. Data collected using a forward looking infrared (FLIR) thermal camera and a Minolta-Land Cyclops 300 thermal infrared thermometer showed that the bulk volume flux of lava flowing in the channel varied greatly over time. Cyclic changes in the channel’s volumetric flow rate occurred over several hours, with cycle durations of 113–190 min, and discharges peaking at 0.7 m3 s−1 and waning to 0.1 m3 s−1. Each cycle was characterized by a relatively short, high-volume flux phase during which a pulse of lava,with awell-defined flow front, would propagate down-channel, followed by a period of waning flow during which volume flux lowered. Pulses involved lava moving at relatively high velocities (up to 0.29 m s−1) and were related to some change in the flow conditions occurring up-channel, possibly at the vent. They implied either a change in the dense rock effusion rate at the source vent and/or cyclic-variation in the vesicle content of the lava changing its bulk volume flux. Pulses would generally overspill the channel to emplace p¯ahoehoe overflows. During periods of waning flow, velocities fell to 0.05 m s–1. Blockages forming during such phases caused lava to back up. Occasionally backup resulted in overflows of slow moving ‘a‘¯a that would advance a few tens of meters down the levee flank. Compound levees were thus a symptom of unsteady flow, where overflow levees were emplaced as relatively fast moving p¯ahoehoe sheets during pulses, and as slow-moving ‘a‘¯a units during backup. Small, localized fluctuations in channel volume flux also occurred on timescales of minutes. Volumes of lava backed up behind blockages that formed at constrictions in the channel. Blockage collapse and/or enhanced flow under/around the blockage would then feed short-lived, wave-like, downchannel surges. Real fluctuations in channel volume flux, due to pulses and surges, can lead to significant errors in effusion rate calculations.
    Description: Published
    Description: 497-515
    Description: reserved
    Keywords: Etna ; FLIR ; Lava channel ; a‘a ; Thermal ; Unsteady flow ; Morphology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 14
    Publication Date: 2017-04-04
    Description: The use of a hand-held thermal camera during the 2002–2003 Stromboli effusive eruption proved essential in tracking the development of flow field structures and in measuring related eruption parameters, such as the number of active vents and flow lengths. The steep underlying slope on which the flow field was emplaced resulted in a characteristic flow field morphology. This comprised a proximal shield, where flow stacking and inflation caused piling up of lava on the relatively flat ground of the vent zone, that fed a medial–distal lava flow field. This zone was characterized by the formation of lava tubes and tumuli forming a complex network of tumuli and flows linked by tubes. Most of the flow field was emplaced on extremely steep slopes and this had two effects. It caused flows to slide, as well as flow, and flow fronts to fail frequently, persistent flow front crumbling resulted in the production of an extensive debris field. Channel-fed flows were also characterized by development of excavated debris levees in this zone (Calvari et al. 2005). Collapse of lava flow fronts and inflation of the upper proximal lava shield made volume calculation very difficult. Comparison of the final field volume with that expecta by integrating the lava effusion rates through time suggests a loss of ~70% erupted lava by flow front crumbling and accumulation as debris flows below sea level. Derived relationships between effusion rate, flow length, and number of active vents showed systematic and correlated variations with time where spreading of volume between numerous flows caused an otherwise good correlation between effusion rate, flow length to break down. Observations collected during this eruption are useful in helping to understand lava flow processes on steep slopes, as well as in interpreting old lava–debris sequences found in other steep-sided volcanoes subject to effusive activity.
    Description: Published
    Description: JCR Journal
    Description: reserved
    Keywords: Lava flow field ; Morphology ; Tumuli ; Lava tubes ; Effusion rate ; Rheology ; Stromboli volcano ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 15
    Publication Date: 2017-04-04
    Description: Bulk atmospheric deposition of major cations (Na, K, Ca, Mg) and anions (Cl, F, SO4) were measured at 15 sites around an active volcano, Mount Etna, from 2001 to 2003. Their composition indicates several natural sources, among which deposition of plume-derived volcanogenic gas compounds is prevalent for F, Cl and S. Plume-derived acidic compounds are also responsible for the prevailing acidic composition of the samples collected on the summit of the volcano (pH in the 2.45–5.57 range). Cation species have complex origin, including deposition of plume volcanogenic ash and aerosols and soil-dust wind re-suspension of either volcanic or carbonate sedimentary rocks. Variation of the deposition rates during the March 2001– March 2003 period, coupled with previous measurements from 1997 to 2000 (Appl Geochem 16:985–1000, 2001), were compared with the variation of SO2 flux, volcanic activity and rainfall. The deposition rate was mainly controlled by rainfall. Commonly, about 0.1–0.9% of HF, HCl and SO2 emitted by the summit crater’s plume were deposited around the volcano. We estimate that ∼2 Gg of volcanogenic sulphur were deposited over the Etnean area during the 2002–2003 flank eruption, at an average rate of ∼24 Mg day−1 which is two orders of magnitude higher than that typical of quiescent degassing phases.
    Description: Published
    Description: 255-265
    Description: JCR Journal
    Description: open
    Keywords: Volcanic degassing ; Etna volcano ; Impact of volcanic eruptions ; S deposition rates ; Halogen deposition rates ; Bulk deposition chemistry ; Environmental volcanology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 16
    Publication Date: 2017-04-04
    Description: Forward Looking Infrared Radiometer (FLIR) cameras offer a unique view of explosive volcanism by providing an image of calibrated temperatures. In this study, 344 eruptive events at Stromboli volcano, Italy, were imaged in 2001–2004 with a FLIR camera operating at up to 30 Hz. The FLIR was effective at revealing both ash plumes and coarse ballistic scoria, and a wide range of eruption styles was recorded. Eruptions at Stromboli can generally be classified into two groups: Type 1 eruptions, which are dominated by coarse ballistic particles, and Type 2 eruptions, which consist of an optically-thick, ash-rich plume, with (Type 2a) or without (Type 2b) large numbers of ballistic particles. Furthermore, Type 2a plumes exhibited gas thrust velocities (〉15 m s−1) while Type 2b plumes were limited to buoyant velocities (〈15 m s−1) above the crater rim. A given vent would normally maintain a particular gross eruption style (Type 1 vs. 2) for days to weeks, indicating stability of the uppermost conduit on these timescales. Velocities at the crater rim had a range of 3–101 m s−1, with an overall mean value of 24 m s−1. Mean crater rim velocities by eruption style were: Type 1= 34 m s−1, Type 2a=31 m s−1, Type 2b=7 m s−1. Eruption durations had a range of 6–41 s, with a mean of 15 s, similar among eruption styles. The ash in Type 2 eruptions originates from either backfilled material (crater wall slumping or ejecta rollback) or rheological changes in the uppermost magma column. Type 2a and 2b behaviors are shown to be a function of the overpressure of the bursting slug. In general, our imaging data support a broadening of the current paradigm for strombolian behavior, incorporating an uppermost conduit that can be more variable than is commonly considered.
    Description: NSF grant no. EAR-0207734, NERC grant no. NER/B/S/2001/00707, the USGS Volcano Hazards Program and the Geophysical Institute at the University of Alaska Fairbanks
    Description: Published
    Description: 769-784
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: reserved
    Keywords: Stromboli volcano ; volcano monitoring ; thermal imaging ; eruption dynamics ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 17
    Publication Date: 2017-04-04
    Description: Measurements of CO2 flux from the ground were periodically carried out on the island of Vulcano (Aeolian Islands, Italy) between 1984 and 1994. Three high-flux areas were identified at the foot of the volcanic cone (La Fossa), either inside or very close to the main village. Effect of the choice of the sampling grid was evaluated. A different sampling grid resulted in similar distribution patterns, but with different CO2 fluxes. Therefore, the absolute estimate of the total flux from the investigated area includes a large degree of uncertainty, but repeated measurements with permanent sampling sites are accurate and can detect small changes. No correlation of the flux with atmospheric parameters was found at sites with high fluxes. Some periods characterized by high CO2 fluxes were observed, and a close correlation was found between the gas emissions from the ground and other geochemical and geophysical parameters such as temperature, chemical composition, steam, and SO2 flux from fumaroles, seismic energy release, and ground deformations. The results show that major temporal variations of diffuse CO2 flux are related to variations in volcanic activity.
    Description: Gruppo Nazionale per la Vulcanologia CNR Italy.
    Description: Published
    Description: 219–228
    Description: partially_open
    Keywords: CO2 ; Flux measurements ; Gas emissions ; Soil gas ; Volcanic activity ; Vulcano ; 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
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  • 18
    Publication Date: 2017-04-04
    Description: Significant changes in the helium and carbon isotopic composition of shallow thermal waters vs. gas and a crater fumarolic gas have been recorded at Stromboli prior and during the 2002–2003 eruption. The 3He/4He ratios corrected for air contamination (Rc/Ra), and δ13C of fumarolic gases gradually increased from May to November 2002 before the eruption onset. These variations imply early degassing of a gas-rich magma at depth that likely fed both the intense Strombolian activity and small lava overflows recorded during that period. The lava effusion of late December 2002 was shortly preceded by a marked Rc/Ra decrease both in water and fumarolic gases. Comparison of He/CO2 and CH4/CO2 ratios in dissolved gas and with δ13CCO2 values rules out the Rc/Ra decrease due to an increasing input of radiogenic 4He. The Rc/Ra decrease is attributed to the He isotope fractionation during rapid magma ascent and degassing. A new uprising of 3He-rich magma probably occurred in January to February 2003, when Rc/Ra ratios displayed the highest values in dissolved gases ever measured before (4.56 Rc/Ra). The increase in He/CO2 and CH4/CO2 ratios and decrease in δ13C of dissolved CO2 was recorded after the 5 April 2003 explosive paroxysm, likely caused by enhanced gas-water interaction inducing CO2 dissolution. No anomalous Rc/Ra values were recorded in the same period, when usual Strombolian activity gradually resumed.
    Description: Published
    Description: 118–134
    Description: partially_open
    Keywords: Stromboli ; Eruption ; Geochemistry ; Helium ; Isotopes ; Magma ascent ; Dissolved gases ; 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
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  • 19
    Publication Date: 2017-04-04
    Description: Continuous monitoring of soil CO2 dynamic concentration (which is proportional to the CO2 flux through the soil) was carried out at a peripheral site of Mt. Etna during the period November 1997 - September 2000 using an automated station. The acquired data were compared with SO2 flux from the summit craters measured two to three times a week during the same period. The high frequency of data acquisition with both methods allowed us to analyze in detail the time variations of both parameters. Anomalous high values of soil CO2 dynamic concentration always preceded periods of increased flux of plume SO2, and these in turn were followed by periods of summit eruptions. The variations were modeled in terms of gas efflux increase due to magma ascent to shallow depth and its consequent depressurization and degassing. This model is supported by data from other geophysical and volcanological parameters. The rates of increase both of soil CO2 dynamic concentration and of plume SO2 flux are interpreted to be positively correlated both to the velocity of magma ascent within the volcano and to lava effusion rate once magma is erupted at the surface. Low rates of the increase were recorded before the nine-month-long 1999 subterminal eruption. Higher rates of increase were observed before the violent summit eruption of September-November 1999, and the highest rates were observed during shorter and very frequent spike-like anomalies that preceded the sequence of short-lived but very violent summit eruptions that started in late January 2000 and continued until late June of the same year. Furthermore, the time interval between the peaks of CO2 and SO2 in a single sequence of gas anomalies is likely to be controlled by magma ascent velocity.
    Description: Consiglio Nazionale delle Ricerche of Italy (C.N.R.)Gruppo Nazionale per la Vulcanologia.
    Description: Published
    Description: 80-89
    Description: partially_open
    Keywords: Mt. Etna ; Soil CO2 emissions ; Plume SO2 flux ; COSPEC ; Continuous geochemical monitoring ; Eruptive activity ; Degassing model ; 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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  • 20
    Publication Date: 2017-04-04
    Description: Ground deformation occurring on the southern flank of Mt Etna volcano during the JulyAugust 2001 eruption was monitored by GPS measurements along an EW profile crossing the fissure system. This profile was measured eight times during the eruption, using the 'stop and go' semi-kinematic technique. Horizontal and vertical displacements between GPS surveys are reported for each station. The most significant event is a deformation episode occurring during the first week of the eruption, between 2527 July. Displacements were measured on benchmarks close to the eruptive fissure and the tensile 1989 fracture. Data inversions for measured displacements were performed using the Okada model. The model shows the narrowing of the 2001 dyke accompanied by a dextral dislocation along an east-dipping fault, parallel to the 1989 fracture.
    Description: Published
    Description: 336-341
    Description: partially_open
    Keywords: GPS ; Ground deformation ; Modelling ; Volcano monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.03. Geodesy::04.03.09. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 21
    Publication Date: 2017-04-04
    Description: The 200203 Mt Etna flank eruption began on 26 October 2002 and finished on 28 January 2003, after three months of continuous explosive activity and discontinuous lava flow output. The eruption involved the opening of eruptive fissures on the NE and S flanks of the volcano, with lava flow output and fire fountaining until 5 November. After this date, the eruption continued exclusively on the S flank, with continuous explosive activity and lava flows active between 13 November and 28 January 2003. Multi-disciplinary data collected during the eruption (petrology, analyses of ash components, gas geochemistry, field surveys, thermal mapping and structural surveys) allowed us to analyse the dynamics of the eruption. The eruption was triggered either by (i) accumulation and eventual ascent of magma from depth or (ii) depressurisation of the edifice due to spreading of the eastern flank of the volcano. The extraordinary explosivity makes the 200203 eruption a unique event in the last 300 years, comparable only with La Montagnola 1763 and the 2001 Lower Vents eruptions. A notable feature of the eruption was also the simultaneous effusion of lavas with different composition and emplacement features. Magma erupted from the NE fissure represented the partially degassed magma fraction normally residing within the central conduits and the shallow plumbing system. The magma that erupted from the S fissure was the relatively undegassed, volatile-rich, buoyant fraction which drained the deep feeding system, bypassing the central conduits. This is typical of most Etnean eccentric eruptions. We believe that there is a high probability that Mount Etna has entered a new eruptive phase, with magma being supplied to a deep reservoir independent from the central conduit, that could periodically produce sufficient overpressure to propagate a dyke to the surface and generate further flank eruptions.
    Description: Published
    Description: 314-330
    Description: partially_open
    Keywords: Multi-disciplinary study ; Mount Etna ; 2002–03 eruption ; Eccentric eruptions ; Flank activity ; Etna feeding system ; Volcanic processes ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 22
    Publication Date: 2017-04-04
    Description: Flank instability and collapse are observed at many volcanoes. Among these, Mt. Etna is characterized by the spreading of its eastern and southern flanks. The eastern spreading area is bordered to the north by the EW-trending Pernicana Fault System (PFS). During the 20022003 Etna eruption, ground fracturing along the PFS migrated eastward from the NE Rift, to as far as the 18 km distant coastline. The deformation consisted of dextral en-echelon segments, with sinistral and normal kinematics. Both of these components of displacement were one order of magnitude larger (~1 m) in the western, previously known, portion of the PFS with respect to the newly surveyed (~9 km long) eastern section (~0.1 m). This eastern section is located along a pre-existing, but previously unknown, fault, where displaced man-made structures give overall slip rates (11.9 cm/year), only slightly lower than those calculated for the western portion (1.42.3 cm/year). After an initial rapid motion during the first days of the 20022003 eruption, movement of the western portion of the PFS decreased dramatically, while parts of the eastern portion continued to move. These data suggest a model of spreading of the eastern flank of Etna along the PFS, characterized by eruptions along the NE Rift, instantaneous, short-lived, meter-scale displacements along the western PFS and more long-lived centimeter-scale displacements along the eastern PFS. The surface deformation then migrated southwards, reactivating, one after the other, the NNWSSE-trending Timpe and Trecastagni faults, with displacements of ~0.1 and ~0.04 m, respectively. These structures, along with the PFS, mark the boundaries of two adjacent blocks, moving at different times and rates. The new extent of the PFS and previous activity over its full length indicate that the sliding eastern flank extends well below the Ionian Sea. The clustering of seismic activity above 4 km b.s.l. during the eruption suggests a deep décollement for the moving mass. The collected data thus suggests a significant movement (volume 〉1,100 km3) of the eastern flank of Etna, both on-shore and off-shore.
    Description: Published
    Description: 417-430
    Description: partially_open
    Keywords: Volcano spreading ; Fracturing ; Mt. Etna ; Pernicana Fault System ; NE Rift ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 23
    Publication Date: 2017-04-04
    Description: Accurate and precisely located self-potential (SP), temperature (T) and CO2 measurements were carried out in the summit area of Stromboli along 72 straight profiles. SP data were acquired every metre and T data every 2.5 m. CO2 concentrations were acquired with the same density as T, but only along seven profiles. The high density of data and the diversity of the measured parameters allows us to study structures and phenomena at a scale rarely investigated. The shallow summit hydrothermal activity (Pizzoâ Fossa area) is indicated by large positive SP, T and CO2 anomalies. These anomalies are focused on crater faults, suggesting that the fracture zones are more permeable than surrounding rocks at Stromboli. The analysis of the distribution of these linear anomalies, coupled with the examination of the geologic, photographic and topographic data, has led us to propose a new structural interpretation of the summit of Stromboli. This newly defined structural framework comprises (1) a large Pizzo circular crater, about 350 m in diameter; (2) a complex of two concealed craters nested within the Pizzo crater (the Large and the Small Fossa craters), thought to have formed during the eruption of the Pizzo pyroclastites unit; the Small Fossa crater is filled with highly impermeable material that totally impedes the upward flow of hydrothermal fluids; and (3) The present complex of active craters. On the floor of the Fossa, short wavelength SP lows are organized in drainage-like networks diverging from the main thermal anomalies and converging toward the topographic low in the Fossa area, inside the Small Fossa crater. They are interpreted as the subsurface downhill flow of water condensed above the thermal anomalies. We suspect that water accumulates below the Small Fossa crater as a perched water body, representing a high threat of strong phreatic and phreatomagmatic paroxysms. T and CO2 anomalies are highly correlated. The two types of anomalies have very similar shapes, but the sensitivity of CO2 measurements seems higher for lowest hydrothermal flux. Above T anomalies, a pronounced high frequency SP signal is observed. Isotopic analyses of the fluids show similar compositions between the gases rising through the faults of the Pizzo and Large Fossa craters. This suggests a common origin for gases emerging along different structural paths within the summit of Stromboli. A site was found along the Large Fossa crater fault where high gas flux and low air contamination made gas monitoring possible near the active vents using the alkaline bottle sampling technique.
    Description: Published
    Description: 486â 504
    Description: partially_open
    Keywords: Carbon dioxide ; Hydrothermal system ; Soil gas ; Stromboli ; 03. Hydrosphere::03.02. Hydrology::03.02.03. Groundwater processes ; 03. Hydrosphere::03.03. Physical::03.03.01. Air/water/earth interactions ; 03. Hydrosphere::03.03. Physical::03.03.02. General circulation ; 04. Solid Earth::04.02. Exploration geophysics::04.02.01. Geochemical exploration ; 04. Solid Earth::04.02. Exploration geophysics::04.02.04. Magnetic and electrical methods ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 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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