ALBERT

Description: The GEOSTAR is a technological and scientific project aimed at the realisation of an autonomous benthic observatory able to perform long-term, continuous and integrated geophysical and environmental measurements in deep seafloors. The observatory is conceived to be a node of existing and future geophysical monitoring networks, making possible their extension offshore. The GEOSTAR observatory prototype hosts sensors for seismic, geomagnetic, gravimetric, geochemical and oceanographic researches up to abyssal depths (4000 m). The first 1-year scientific mission is foreseen within the end of the millennium in the abyssal plain (3400 m) of the Southern Tyrrhenian Sea, where key information about the geodynamics and oceanography of the whole Mediterranean basin can be acquired.

Description: Published

Description: 175-183

Description: JCR Journal

Description: reserved

Description: The Educational & Outreach Group of the Istituto Nazionale di Geofisica e Vulcanologia (INGV, Rome, Italy) designed a portable museum to bring on the road educational activities focused on the understanding of geomagnetism, plate tectonics, seismology and seismic hazard. Here the main experiments, models and exhibits which have been successfully installed in Genoa for the Science Festival (2003, 2004) and in Rome (2005) with enthusiastic audience participation are shown.

Description: Published

Description: 375-381

Description: 5.8. TTC - Formazione e informazione

Description: N/A or not JCR

Description: open

Description: Geophysics Open archive. Free access to worldwide scientists during search and submission process. Earth-Prints is an open archive created and maintained by Istituto Nazionale di Geofisica e Vulcanologia with the collaboration of Programma Nazionale Ricerche in Antartide. It is maintained by CILEA .

Description: Unpublished

Description: Rome, Italy

Description: open

Description: For Geosystemics we define the science that studies the Earth system from a holistic point of view. Earth is thus considered as a whole and unique far-from-the equilibrium complex system, formed by numerous different parts (sub-systems), which do not act independently but interact each other continuously. Most interactions are nonlinear, so that we can usually say that “resultant is more than the sum of the parts”. Interactions are not only in terms of contrasts but, and mostly, cooperative and mutual organizations. We will see some aspects and properties of this approach with a few examples.

Description: Published

Description: Cambridge, UK, February 24-26, 2009

Description: 3.3. Geodinamica e struttura dell'interno della Terra

Description: open

Description: The present paper describes a multidisciplinary approach to the evaluation of a seismically triggered landslide that occurred in the Cerda area (Italy) on September 6, 2002, about 1 h after an earthquake took place in the south Tyrrhenian Sea. The study was focused on an analysis of the role of the seismic input in triggering the landslide, in view of the evidence that no other mass movement was recorded in the adjacent areas despite geological and geomorphological spatial homogeneity. The studied area is located on a slope of the western flank of the Fiume Imera Settentrionale (Northern Sicily), which is made up of clayey–arenitic rocks. The slope inclines gently but is not uniform due to fluvial, gravitative, and rainwash processes. Field data dealing with global positioning system (GPS), geology, geomorphology, geophysics (vertical electrical sounding, or VES), and geochemistry (soil gas fluxes and composition) were acquired and analysed in order to investigate the cause–effect relationships between the earthquake and the mass movement. The GPS survey allowed us to map the ground failures that have also been classified on the basis of their kinematical meaning (i.e., compressive, distensive, or transcurrent structures). The geological analysis revealed outcropping rocks and tectonic structures. The geomorphologic survey highlighted the presence of preexisting landslide bodies. The geophysical survey detected a buried surface located at a depth of about 100 m . Finally, the geochemical survey showed that the gas released from the displaced mass came from a shallow depth and was not related to any active fault system. The abovementioned information allowed us to interpret the landslide event as a partial reactivation of a preexisting landslide body that was triggered by the earthquake.

Description: Ministero dell’Istruzione, dell’Universita` e della Ricerca (MIUR), Cofinanziamento Progetti di Ricerca di Rilevante Interesse Nazionale (COFIN PRIN) 2002 Project "Valutazione dell’Erosione del Suolo in Ambiente Mediterraneo"

Description: Published

Description: 101–116

Description: partially_open

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2001

Description: Half of the ocean crust is formed at spreading centers with total opening rates less than 40 km/Myr. The objective of this Thesis is to investigate temporal variations in active ridge processes and crustal aging at slow-spreading centers by comparing axial crustal structure with that on conjugate flanks of the slow-spreading Mid-Atlantic Ridge (MAR) (full rate, 20 km/Myr) and the ultra-slow spreading Southwest Indian Ridge (SWIR) (full rate, 14 km/Myr). Seismic refraction data collected along the rift valley and flanking rift mountains of the OH-l segment (35°N) at the MAR show that the entire crustal section is constructed within a zone that is less than 5 km wide. Shallow-level hydrothermal circulation within the axial valley is suggested by the rift mountain seismic profiles, which show that the upper crust is 20% thinner and 16% faster along strike than zero-age crust. These effects probably result from fissure sealing within the extrusive crust. Deeper crustal velocities remain relatively constant at the segment midpoint within the first 2 Myr, but are reduced near the segment offsets presumably by faulting and fracturing associated with uplift out of the rift valley. A temporal variation in axial melt supply is suggested by a 15% difference in along-strike crustal thickness between the rift valley and rift mountains, with relatively less melt supplied today than 2 Ma. Crustal accretion at the SWIR appears to occur in a similar manner as at the MAR, although gravity and seismic data indicate that the average crustal thickness is 2-4 km less at the ultra-slow spreading SWIR. A 25 Myr record on both flanks of the ridge shows that seafloor spreading has been highly asymmetric through time, with 35% faster crustal accretion on the Antarctic (south) plate. A small-offset non-transform discontinuity between two ridge segments is just as stable as two neighboring transform discontinuities, although a single mantle Bouguer gravity anomaly centered over the non-transform offset indicates that this boundary does not significantly perturb underlying mantle flow. Off-axis magnetic anomalies are recorded with high fidelity despite the very low spreading rates and the absence of a basaltic upper crust in one area. The lower crust may be the dominant off-axis carrier of the magnetic signal, contrary to traditional models of crustal magnetic structure. Morphological and gravity data show evidence of asymmetric crustal accretion across the SWIR ridge axis, with slightly warmer mantle temperatures beneath the slower-spreading African (north) plate.

Description: Funding was provided by the National Science Foundation through Contract No. OCE-9300450 and by the Joint Oceanographic Institutions through Subcontract No. JSC1-00.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June, 1980

Description: This thesis consists of three papers applying the techniques of time series analysis to geophysical data. Surface wave dispersion along the Walvis Ridge, South Atlantic Ocean, is obtained by bandpass filtering the recorded seismogram in the frequency domain. The group velocity is anomalously low in the period range of 15-50 s, and formal inversion of the data indicates both crustal thickening to 12.5 km and low shear velocity (4.25-4.35 km/s) to depths of 40-50 km. The electromagnetic induction fields at a deep ocean site northeast of Hawaii were used to determine the electrical conductivity of the earth to 400 km depth. Singular value decomposition of the data matrix indicates three degrees of freedom, suggesting source field complications and a two dimensional conductive structure. Inversion of one of the principal terms in the response function shows an abrupt rise in electrical conductivity to 0.05 mho/m near 160 km with no resolvable decrease below this. A model study suggests that moving source fields influence the induction appreciably in the other principal response tunction. A set of piston cores from the northeast Atlantic Ocean are used to construct paleomagnetic time series covering the interval 25-127 kybp. Stratigraphic control is provided by counts of planktonic toraminifera, and empirical orthogonal function analysis shows a significant decrease in sedimentation rate at the interglaciai/glacial transition. The sediments are magnetically stable and reliable relative paleointensity measurements could be obtained. Spectral analysis of the directions reveals a predominant 10 ky periodicity and no dominant looping direction.

Description: I was supported for the early parts of this work by a NSF Graduate Fellowship. The Walvis Ridge study was supported by the WHOI Education Office and the Defense Advanced Research Projects Agency. The induction study was funded by the NSF under grants OCE74-12730 and OCE77-8633, and by the WHOI Ocean Industries Program. The paleomagnetic study was supported by NSF contracts OCE77-82255 and ÖCE79-19258.

Description: The primary objective of this publication is to share with a wider audience the valuable information and extensive dialogue that took place amongst over 140 individuals who attended the second in a series of planned workshops on the science and management of coastal landforms in Massachusetts. This workshop took place at the Woods Hole Oceanographic Institution on January 24, 2001. The individuals who attended this workshop are actively engaged in planning, managing, regulating, engineering, educating, and studying coastal landforms and their beneficial functions. This workshop titled, Can Humans & Coastal Landforms Co-exist?’, was a natural follow-up to a previous workshop, Coastal Landform Management in Massachusetts, held at WHOI October 9-10, 1997 (proceedings published as WHOI Technical Report #WHOI-98-16). The workshop had a very practical, applied focus, providing state-of-the-art scientific understanding of coastal landform function, case history management and regulation of human activities proposed on coastal landforms, a multi-faceted mock conservation commission hearing presented by practicing technical consultants and attorneys that involved all attendees acting as regulators in breakout sessions, and, at the conclusion of the workshop, an open discussion on all issues related to the science and management of coastal landforms, including future research needs.

Description: Funding for these proceedings was provided by WHOI Sea Grant and the NOAA National Sea Grant College Program Office, Department of Commerce, under NOAA Grant No. M10-2, Woods Hole Oceanographic Institution Sea Grant Project No. NA86R60075.

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September, 1975

Description: The Mid-Atlantic Ridge is one of the most well known and yet poorly understood spreading centers in the world. A detailed investigation of the Mid-Atlantic Ridge crest near 37°N (FAMOUS) was conducted using a deeply towed instrument package. The objective was to study the detailed structure and spreading history of the Mid-Atlantic Ridge median valley, to explore the roles of volcanism and faulting in the evolution of oceanic crust, and to study the morphologic expression and structural history of the zone of crustal accretion. In addition, microearthquake surveys were conducted using arrays of free-floating hydrophones. The most recent expression of the accreting plate boundary in the Famous Rift is an alternating series of linear central volcanoes and depressions 1.5 km wide which lie within the inner floor. This lineament is marked by a sharp maximum in crustal magnetization only 2-3 km wide. Magnetic studies indicate that over 90% of the extrusive volcanism occurs within the rift inner floor, a zone 1 to 12 km wide, while volcanism is extremely rare in the rift mountains. Volcanoes created in the inner floor are transported out on, block faults, becoming a lasting part of the topography. Magnetic anomaly transition widths vary from 1 km to 8 km with time and appear to reflect a bi-stable median valley structure. The valley has either a wide inner floor and narrow terraces, in which case the volcanic zone is wide and magnetic anomalies are poorly recorded (wide transition widths); or it has a narrow inner floor and wide terraces, the volcanic zone is then narrow and anomalies are clearly recorded (narrow transition widths). The median valley of any ridge segment varies between these two structures with time. At present the. Famous Rift has a narrow inner floor and volcanic zone (1-3 km) while the south Famous Rift is at the opposite end of the cycle with a wide inner floor and volcanic zone (10-12 km). Over 95% of the large scale (〉2 km) relief of the median valley is accounted for by normal faults dipping toward the valley axis. Normal faulting along fault planes dipping away from the valley begins just past the outer walls of the valley. Outward facing normal faulting accounts for most of the decay of median valley relief in the rift mountains while crustal tilting accounts for less than 20%. The pattern of normal faulting creates a broad, undulating horst and graben relief. Volcanic features contribute little to the large scale relief, but contribute to the short wavelength (〈2km) roughness of the topography. Spreading in the Famous area is highly asymmetric with rates twice as high to the east as to the west. At 1.7 m.y.b.p. the sense of asymmetry reverses in direction with spreading faster to the west, resulting in a gross symmetry when averaged through time. The change in spreading asymmetry occurred in less than 0.15 m.y. Structural studies indicate that the asymmetric spreading is accomplished through asymmetric crustal extension as well as asymmetric crustal accretion. Spreading in the Famous area is 17° oblique. Even on a fine scale there is no indication of readjustment to an orthogonal plate boundary system. Spreading has been stably oblique for at least 6 m.y., even through a change in spreading direction. Magnetic studies reveal that the deep DSDP hole at site 332 was drilled into a magnetic polarity transition, and may have sampled rocks which recorded the earth i s field behavior during a reversal. The presence of negative polarity crust within the Brunhes normal epoch in the inner floor has been determined, and may be due to old crust left behind or recording of a geomagnetic field event. Crustal magnetization decays to lie of its initial value in less than 0.6 m.y. The rapid decay may be facillitated by very intense crustal fracturing observed in the inner floor. Microearthquake, magnetic and structural studies indicate that both the spreading and transform plate boundaries are very narrow (1-2 km) and well-defined for short periods, but migrate over zones 10-20 km wide through time.

Description: MapTool is an interactive computer program for the display of common marine geophysical data. At present, the program displays isolines, color-filled contours, navigation tracklines, and navigated scalar values in a variety of styles. A variety of map projections are supported. This document describes the basic requirements for running the MapTool program, for creating various displays, and generating hard copy output. The supported data file formats are described. All of the options, displays, menus, and windows are documented.

Description: Funding was provided by the Office of Naval Research under Grant N00014-90-J-1621.