DSpace Collection:

The concept of geological time

Mon, 31 Dec 2012 23:00:00 GMT

Title: The concept of geological time Authors: Ricciardi, G. P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia Editors: Varadinis, M.; Kunsthaus Zurich; Barba, R. Abstract: From the remote past, with the transition from an existence as nomadic hunters to one farming the land,humankind felt the need to find a systematic way to measure time,prompted by the necessity to arrange the events that occurred in his life into an orderly sequence...

Terremoto in Emilia Romagna (2012): le attività del Centro Operativo Emergenza Sismica

Tue, 12 Feb 2013 23:00:00 GMT

Title: Terremoto in Emilia Romagna (2012): le attività del Centro Operativo Emergenza Sismica Authors: Moretti, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Pondrelli, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Abstract: Come definito negli accordi riportati nell’ambito della Convenzione1 esistente tra l’Istituto Nazionale di Geofisica e Vulcanologia (INGV) e il Dipartimento di Protezione Civile (DPC), a poche ore dal forte terremoto che nella notte del 20 maggio 2012 ha colpito una vasta area dell’Emilia [Moretti et al., 2012; 2013a], è stato attivato il Pronto Intervento Sismico dell’INGV [Govoni et al., 2008; Moretti e Govoni, 2011; Moretti et al., 2010c]. Durante la prima settimana dell’emergenza l’obiettivo principale della struttura emergenziale INGV ha riguardato il miglioramento del monitoraggio sismico; sono state quindi attivate le reti sismiche mobili [maggiori dettagli in Moretti et al., 2012; 2013a] con il fine di integrare le stazioni permanenti della Rete Sismica Nazionale [RSN, Amato e Mele, 2008; Delladio et al., 2011]. Solo in una secondo momento, dopo circa 10 giorni dall’inizio della sequenza sismica è stato ufficialmente attivato il Centro Operativo Emergenza Sismica [COES, Moretti et al., 2010a], a seguito del decreto del Capo del DPC, con il quale è stata costituita la Direzione di Comando e Controllo (Di.Coma.C.2) presso l’Agenzia della Protezione Civile Regionale dell’Emilia Romagna (AgDPC) in Bologna. L’allestimento e il coordinamento del COES sono stati realizzati grazie alla collaborazione tra il Centro Nazionale Terremoti (CNT), a cui afferisce la struttura, e la Sezione INGV di Bologna, sita nel capoluogo della regione colpita dall’emergenza. In questo lavoro saranno descritte le modalità, le tempistiche e l’impegno di personale che hanno permesso e garantito l'attivazione e il buon funzionamento del COES.

Sequence stratigraphy, kinematics and dynamic geohistory of the Crotone Basin (Calabrian Arc, Central Mediterranean): an integrated approach

Sun, 31 Dec 1989 23:00:00 GMT

Title: Sequence stratigraphy, kinematics and dynamic geohistory of the Crotone Basin (Calabrian Arc, Central Mediterranean): an integrated approach Authors: van Dijk, J. P.; Eni Abstract: A comprehensive study of the Late Neogene tectonostratigraphic development of the Crotone Basin is presented. The basin is situated on the accretionary wedge along the external side of the Calabrian Arc (Central Mediterranean). The results of our analysis provide detailed insight into the relative role of local tectonic activity of the thrust wedge and regional relative sea level fluctuations in the creation of unconformity bound depositional sequences. The tectonostratigraphic significances of the sequence boundaries of the Early-Late Miocene and Late Pliocene-middle Pleistocene sequences are remarkably similar. They reflect a “composite tectonic event” comprising an uplift/regression pulse, followed by a rapid subsidence/onlap. Each composite tectonic event, in turn, represents one pulse in the progressive evolution of the accretionary wedge system. We regard the middle Messinian-Early Pliocene phases of basin fill and tectonic inversion, and the Late Pleistocene-Recent uplift phase as reflections of the increase of regional stress in the Central Mediterranean.

Geological and geophysical investigation of Kamil crater, Egypt

Thu, 13 Dec 2012 23:00:00 GMT

Title: Geological and geophysical investigation of Kamil crater, Egypt Authors: Urbini, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Nicolosi, I.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Zeoli, A.; Museo Nazionale dell’Antartide Universita` di Siena, Via Laterina 8, 53100 Siena, Italy; El Khrepy, S.; National Research Institute of Astronomy and Geophysics, Helwan, Egypt; Lethy, A.; National Research Institute of Astronomy and Geophysics, Helwan, Egypt; Hafez, M.; National Research Institute of Astronomy and Geophysics, Helwan, Egypt; El Gabry, M.; National Research Institute of Astronomy and Geophysics, Helwan, Egypt; El Barkooky, A.; Department of Geology, Faculty of Sciences, Cairo University, Giza, Egypt; Barakat, A.; Egyptian Mineral Resources Authority, 3 Salah Salem Road, Abassiya, Cairo, Egypt; Gomaa, M.; Museo Nazionale dell’Antartide Universita` di Siena, Via Laterina 8, 53100 Siena, Italy; Radwan, A. M.; Museo Nazionale dell’Antartide Universita` di Siena, Via Laterina 8, 53100 Siena, Italy; El Sharkawi, M.; Department of Geology, Faculty of Sciences, Cairo University, Giza, Egypt; D’Orazio, M.; Dipartimento di Scienze della Terra, Universita` di Pisa, Via S. Maria 53, 56126 Pisa, Italy; Folco, L.; Dipartimento di Scienze della Terra, Universita` di Pisa, Via S. Maria 53, 56126 Pisa, Italy Abstract: We detail the Kamil crater (Egypt) structure and refine the impact scenario, based on the geological and geophysical data collected during our first expedition in February 2010. Kamil Crater is a model for terrestrial small-scale hypervelocity impact craters. It is an exceptionally well-preserved, simple crater with a diameter of 45 m, depth of 10 m, and rayed pattern of bright ejecta. It occurs in a simple geological context: flat, rocky desert surface, and target rocks comprising subhorizontally layered sandstones. The high depth-to-diameter ratio of the transient crater, its concave, yet asymmetric, bottom, and the fact that Kamil Crater is not part of a crater field confirm that it formed by the impact of a single iron mass (or a tight cluster of fragments) that fragmented upon hypervelocity impact with the ground. The circular crater shape and asymmetries in ejecta and shrapnel distributions coherently indicate a direction of incidence from the NW and an impact angle of approximately 30 to 45 . Newly identified asymmetries, including the off-center bottom of the transient crater floor downrange, maximum overturning of target rocks along the impact direction, and lower crater rim elevation downrange, may be diagnostic of oblique impacts in well-preserved craters. Geomagnetic data reveal no buried individual impactor masses >100 kg and suggest that the total mass of the buried shrapnel >100 g is approximately 1050–1700 kg. Based on this mass value plus that of shrapnel >10 g identified earlier on the surface during systematic search, the new estimate of the minimum projectile mass is approximately 5 t.

La Rete GPS Permanente della Regione Abruzzo

Tue, 30 Nov 2010 23:00:00 GMT

Title: La Rete GPS Permanente della Regione Abruzzo Authors: D'Anastasio, Elisabetta; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; D'Agostino, Nicola

Volcanoes: effusions and explosions. Interactive exhibits to understand how volcanoes work

Tue, 31 Mar 2009 22:00:00 GMT

Title: Volcanoes: effusions and explosions. Interactive exhibits to understand how volcanoes work Authors: C. Nostro, L. Freda, C. Castellano, L. Arcoraci, E. Baroux, M. Pignone, A. Tertulliani, M. De Lucia, M. Di Vito, P. Landi, P. Madonia, M. Martini, R. Nave, M. Neri, P. Scarlato, J. Taddeucci, R. Moschillo, S. Tarquini, G. Vilardo, A. Bonforte, L. Calderone, F. Cannavò, W. De Cesare, P. Ficeli, S. Inguaggiato, M. Mattia, G. Puglisi, S. Morici, D. Reitano, D. Richichi, G. Scarpato, B. Angioni, F. Di Laura, S. Palone, D. Riposati; Istituto Nazionale di Geofisica e Vulcanologia, Sezione AC, Roma, Italia Abstract: The Educational & Outreach Group (EOG) of the Istituto Nazionale di Geofisica & Vulcanologia created a portable museum to provide educational opportunities in volcanology, volcanic risk and Earth science for students and visitors. The EOG developed this project for the "Festival della Scienza", organized in Genoa, Italy, in October - November, 2007, which was a parade of over 200 events, including scientific and technological exhibitions, workshops, meetings, lectures, books and video presentations. In this museum visitors can successively see many posters and movies and play with interactive exhibits. A little 3D-movie shows the Big Bang, the formation of Solar System and, in particular the formation of the Earth. Many interactive exhibits illustrate why, where and when earthquakes and volcanic eruptions occur around the world and allow to introduce the visitor to the plate tectonics theory. A 3D magnetic plate tectonic puzzle can be put down and reconstructed by visitors to understand the Earth’s surface configuration. Then two other 3D Earth models show what drives the plates and the inner Earth structure. An interactive program illustrates where and when earthquakes and volcanic eruptions occur in accelerated time on maps of various areas around the world. Playing with a block diagram it is possible to produce an earthquake along a 1 meter long strike slip fault in a destroying all the man-made constructions close to it. A little movie introduces to volcanoes’ world. Two small interactive exhibits allow visitors to understand the mechanism for the explosive and the effusive eruptions. Two other exciting interactive exhibits allow visitors to “create” two different eruptions: the explosive and the effusive ones. It is possible to get inside a volcano (a 2 meter high interactive exhibit) to attend an eruption from the magmatic chamber to the Earth surface. A big hall is completed dedicated to Italian volcanoes (Vesuvio, Campi Flegrei, Etna, Stromboli, Vulcano, Colli Albani); some of them are reproduced with 3D models or described by short movies. The museum finishes with the visit of the volcanic survey hall of Stromboli, seeing - in real time - seismic data, three different webcams, geochemical and strain data. The INGV Museum had remarkably successful, reaching more than 7,500 children and adults yet in 13 days, also thanks to 30 volcanologists as very special guides. The Educational & Outreach Group: M. Pignone, A. Tertulliani, M. De Lucia, M. Di Vito, P. Landi, P. Madonia, M. Martini, R. Nave, M. Neri, P. Scarlato, J. Taddeucci, R. Moschillo, S. Tarquini, G. Vilardo, A. Bonforte, L. Calderone, F. Cannavò, W. De Cesare, P. Ficeli, S. Inguaggiato, M. Mattia, G. Puglisi, S. Morici, D. Reitano, D. Richichi, G. Scarpato, B. Angioni, F. Di Laura, S. Palone, D. Riposati

Renewal models of seismic recurrence applied to paleoseismological and historical observations

Tue, 04 Sep 2012 22:00:00 GMT

Title: Renewal models of seismic recurrence applied to paleoseismological and historical observations Authors: Mosca, I.; Department of Earth and Environmental Sciences, LMU, Munich, Germany; Console, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; D'Addezio, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia Abstract: Because paleoseismology can extend the record of earthquakes back in time up to several millennia, it represents an opportunity to study how earthquakes recur through time and thus to provide innovative contributions to seismic hazard assessment. Based on a database of recurrence from paleoseismology we collected 19 sequences with 5 up to 14 dated events on a single fault. By using the age of the paleoearthquakes, with their associated uncertainty, and the historical earthquakes, we tested the null hypothesis that the observed inter-event times come from a uniform random distribution (Poisson model). We used the concept of likelihood for a speci!c sequence of events under a given occurrence model. The difference dlnL of the likelihoods estimated under two hypotheses gives an indication of which between the two hypotheses !ts better the observations. To take into account the uncertainties, we used a Monte Carlo procedure computing the average and the standard deviation of dlnL for 1000 inter-event sets by choosing the occurrence time of each event within the limits of uncertainty and estimating the probability that a value equal to or larger than an observed dlnL comes by chance from a Poisson distribution of inter-event times. These tests were carried out for the Log-normal, Gamma, Weibull, Double-exponential and Brownian Passage Time (BPT) distributions. Our results show that a renewal model, associated with a time dependent hazard, and some kind of predictability of the next large earthquake on a fault is signi!cantly better than a plain time-independent Poisson model only for four, out of the 19 sites examined in this study. The lack of regularity in the earthquake occurrence for more than 30% of the examined faults can be explained either by the large uncertainties in the estimate of paleoseismological occurrence times or by physical interaction between neighboring faults.

Distensional Mediterranean and World Orogens

Sat, 31 Dec 2011 23:00:00 GMT

Title: Distensional Mediterranean and World Orogens Authors: Scalera, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia Editors: Scalera, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Cwojdzinski, S. Abstract: An overview of the modern progresses of the expanding Earth conceptions as they come out from new data and their possible interpretations is provided in this paper. The starting point of this review is the new detailed 3D distributions of relocated hypocenters laying under orogenic belts. The similarity of the hypocentral patterns under the Tethyan orogenic belts, and under the South American Pacific orogenic margin is considered to be a major font of information on which to build a more realistic global geodynamic model. Clusters and filaments of hypocenters are recognizable instead of regular patterns. These clusters taper downwards, leading to the idea of a deep origin in narrow regions of disturbance, besides other important facts that witness in favour of surfaceward movements of deep material along what can be called "mega-dykes". The outpouring of the material on the surface produces gravitational nappes and their overthrust on the sediments of the preexisting trough, forcing them on a burial path which emulate the subduction process, but without reaching depths greater than 50-70 km. Phenomenons like metamorphism, mixing, migmization, upward transport of fragments of the buried lithosphere etc. are possible at the boundary between uplifting material and down-pushed crust and lithosphere. Additional clues can be collected that confirm the new proposed framework. The astronomical indications of a coseismic displacement of the instantaneous Earth’s rotation axis in the occasion of the great Sumatra (Mw=9.3) and Honshu (Mw=9.0) earthquakes are especially significant because in complete disagreement with the plate tectonics modelled axis shift and in agreement with the shift expected in the new conception. Because of analogous opposite predictions of the length of day variation following the extreme magnitude earthquakes (ΔLOD<0 vs ΔLOD>0), future improvements of the time measurement techniques could allow a final choice between rival geodynamical models.

How do volcanic rift zones relate to flank instability? Evidence from collapsing rifts at Etna

Tue, 18 Sep 2012 22:00:00 GMT

Title: How do volcanic rift zones relate to flank instability? Evidence from collapsing rifts at Etna Authors: Ruch, J.; Dipartimento Scienze Geologiche, Università Roma Tre, Roma, Italy; Pepe, S.; National Research Council (CNR), Istituto per il Rilevamento Elettromagnetico dell'Ambiente (IREA), Napoli, Italy; Casu, F.; National Research Council (CNR), Istituto per il Rilevamento Elettromagnetico dell'Ambiente (IREA), Napoli, Italy; Acocella, V.; Dipartimento Scienze Geologiche, Università Roma Tre, Roma, Italy; Neri, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Solaro, G.; National Research Council (CNR), Istituto per il Rilevamento Elettromagnetico dell'Ambiente (IREA), Napoli, Italy; Sansosti, E.; National Research Council (CNR), Istituto per il Rilevamento Elettromagnetico dell'Ambiente (IREA), Napoli, Italy Abstract: Volcanic rift zones, characterized by repeated dike emplacements, are expected to delimit the upper portion of unstable flanks at basaltic edifices. We use nearly two decades of InSAR observations excluding wintertime acquisitions, to analyze the relationships between rift zones, dike emplacement and flank instability at Etna. The results highlight a general eastward shift of the volcano summit, including the northeast and south rifts. This steadystate eastward movement (1-2 cm/yr) is interrupted or even reversed during transient dike injections. Detailed analysis of the northeast rift shows that only during phases of dike injection, as in 2002, does the rift transiently becomes the upper border of the unstable flank. The flank's steady-state eastward movement is inferred to result from the interplay between magmatic activity, asymmetric topographic unbuttressing, and east-dipping detachment geometry at its base. This study documents the first evidence of steady-state volcano rift instability interrupted by transient dike injection at basaltic edifices.

Introduction: The ANDRILL McMurdo Ice Shelf (MIS) and Southern McMurdo Sound (SMS) Drilling Projects

Thu, 31 May 2012 22:00:00 GMT

Title: Introduction: The ANDRILL McMurdo Ice Shelf (MIS) and Southern McMurdo Sound (SMS) Drilling Projects Authors: Paulsen, T. S.; Department of Geology, University of Wisconsin Oshkosh, Oshkosh, Wisconsin 54901, USA; Pompilio, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia; Niessen, F.; Alfred Wegener Institute for Polar and Marine Research, D-27568 Bremerhaven, Germany; Panter, K.; Department of Geology, Bowling Green State University, Bowling Green, Ohio 43403-0218, USA; Jarrard, R. D.; Department of Geology and Geophysics, 383 FASB, University of Utah, 115 S. 1460 East, Salt Lake City, Utah 84112-0102, USA Abstract: No Abstract