http://hdl.handle.net/2122/98 Ricerca nel canale cerca http://www.earth-prints.org/simple-search http://hdl.handle.net/2122/5754 Titolo: Correlation of Static Stress Changes and Earthquake Occurrence in<br/><br/>Autori: Rhoades, D. A.; GNS Science, Lower Hutt, New Zealand; Papadimitriou, E. E.; Geophysics Department, University of Thessaloniki, GR54124 Thessaloniki, Greece; Karakostas, V. G.; Geophysics Department, University of Thessaloniki, GR54124 Thessaloniki, Greece; Console, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Murru, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia<br/><br/>Abstract: A systematic analysis is made of static Coulomb stress changes andearthquake occurrence in the area of the North Aegean Sea, Greece, in order to assess theprospect of using static stress changes to construct a regional earthquake likelihoodmodel. The earthquake data set comprises all events of magnitude M ≥ 5.2 which haveoccurred since 1964. This is compared to the evolving stress field due to constant tectonicloading and perturbations due to coseismic slip associated with major earthquakes (M ≥6.4) over the same period. The stress was resolved for sixteen fault orientation classes,covering the observed focal mechanisms of all earthquakes in the region. Analysis usingerror diagrams shows that earthquake occurrence is better correlated with the constanttectonic loading component of the stress field than with the total stress field changes since1964, and that little, if any, information on earthquake occurrence is lost if only themaximum of the tectonic loading over the fault orientation classes is considered.Moreover, the information on earthquake occurrence is actually increased by taking themaximum of the evolving stress field since 1964, and of its coseismic–slip component,over the fault orientation classes. The maximum, over fault orientation classes, of linearcombinations of the tectonic loading and the evolving stress field is insignificantly bettercorrelated with earthquake occurrence than the maximum of the tectonic loading by itself.A composite stress–change variable is constructed from ordering of the maximumtectonic loading component and the maximum coseismic–slip component, in order tooptimize the correlation with earthquake occurrence. The results indicate that it would bedifficult to construct a time–varying earthquake likelihood model from the evolving stressfield that is more informative than a time–invariant model based on the constant tectonicloading.<br/><br/>Descrizione: A systematic analysis is made of static Coulomb stress changes andearthquake occurrence in the area of the North Aegean Sea, Greece, in order to assess theprospect of using static stress changes to construct a regional earthquake likelihoodmodel. Thu, 01 Jan 2009 00:00:00 GMT http://hdl.handle.net/2122/5751 Titolo: Retrospective forecasting of M≥4.0 earthquakes in New Zealand<br/><br/>Autori: Console, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Murru, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Falcone, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia<br/><br/>Abstract: We have applied a variation of the ETAS model, which is a stochastic triggering epidemic model incorporating short-term clustering, to data collected by the New Zealand Seismological Observatory-Wellington (Geonet) for forecasting earthquakes of moderate and large magnitude in the New Zealand region. The model uses earthquake data only, with no explicit use of tectonic, geologic, or geodetic information. In this epidemic-type model every earthquake is regarded, at the same time, as being triggered by previous events and triggering following earthquakes.A maximum likelihood estimate of the model parameters has been performed on the learning period from 1960 to 2005 for earthquakes of magnitude 4.0 and larger. Forecast verification procedures have been carried out in forward-retrospective way on the January 2006-April 2008 data set, making use of statistical tools as the log-likelihood ratio, the Relative Operating Characteristics (ROC) diagrams, the Molchan error diagrams, the probability gain and the R-score. These procedures show that the clustering epidemic model achieves a log-likelihood ratio per event of the order of some units, and a probability gain up to several hundred times larger than a time-independent spatially uniform random forecasting hypothesis. The results show also that a significant component of the probability gain is linked to the time-independent spatial distribution of the seismicity used in the model.<br/><br/>Descrizione: We have applied a variation of the ETAS model, which is a stochastic triggering epidemic model incorporating short-term clustering, to data collected by the New Zealand Seismological Observatory-Wellington (Geonet) for forecasting earthquakes of moderate and large magnitude in the New Zealand region. Thu, 01 Jan 2009 00:00:00 GMT http://hdl.handle.net/2122/5677 Titolo: Earthquake occurrence models in the short and long term for the Italian seismicity<br/><br/>Autori: Falcone, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Console, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Murru, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia<br/><br/>Abstract: This work describes three earthquake occurrence models, two in the short-(24 hour) and one in long-term (5- and 10 year), applied to the whole Italian territory in order to assess the occurrence probability of future (M≥5.0) earthquakes. The first model for short-term forecasts is a purely stochastic Epidemic Type Earthquake Sequence model (ETES). The second short-term epidemic forecast is based on a model physically constrained by the application of Dieterich rate-stateconstitutive law to the earthquake clustering (ERS). The third forecast is based on a Long Term model that considers the perturbation of earthquake probability for interacting faults by static Coulomb stress changes (LTST). These models have been submitted to the CSEP (Collaboratory for the study of Earthquake Predictability) forecast testing for Italy (ETH-Zurich) and locked down to test their validity on real data in a forward way starting from August 1, 2009.<br/><br/>Descrizione: The ETES, ERS and LTST models have been submitted to the CSEP (Collaboratory for the study of Earthquake Predictability) forecast testing for Italy (ETH-Zurich) and locked down to test their validity on real data in a forward way starting from August 1, 2009. Thu, 01 Jan 2009 00:00:00 GMT http://hdl.handle.net/2122/5643 Titolo: "Preface" at "COST 296 MIERS Mitigation of Ionospheric Effects on Radio Systems FINAL REPORT<br/><br/>Autori: Bourdillon, A.; IETR, Université de Rennes 1, France; Cander, L. R.; STFC, Rutherford Appleton Laboratory, Chilton, UK; Zolesi, B.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia<br/><br/>Abstract: N. A. Sat, 01 Aug 2009 00:00:00 GMT http://hdl.handle.net/2122/5249 Titolo: COST 296 scientific results designed for operational use<br/><br/>Autori: Stanislawska, I.; Space Research Centre PAS, Warsaw, Poland; Belehaki, A.; National Observatory of Athens, Athens, Greece; Jakowski, N.; DLR, Institute of Communications and Navigation, Neustrelitz, Germany; Zolesi, B.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Gulyaeva, T. L.; IZMIRAN, Troitsk, Moscow Region, Russia; Cander, L. R.; Rutherford Appleton Laboratory, Chilton, UK; Reinisch, B. W.; Center for Atmospheric Research, UMass Lowell, USA; Pezzopane, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Tsagouri, I.; National Observatory of Athens, Athens, Greece; Tomasik, L.; Space Research Centre PAS, Warsaw, Poland; Galkin, I.; Center for Atmospheric Research, UMass Lowell, USA<br/><br/>Abstract: The main objective of the COST 296 Action «Mitigation of Ionospheric Effects on Radio Systems» is the establishment/improvement of ionospheric services by coordinating the development of specific algorithms, models, and tools capable of operating in a near-real-time mode.Key elements of these activities are contributions related to monitoring, modelling, and imaging of customer-relevantionospheric quantities. COST stimulates, coordinates, and supports Europe’s goals of development and global cooperation by providing high quality information and knowledge of ionospheric and plasmaspheric conditions enabling high quality and reliable operation of radio systems.It also provides a platform for sharing such tools as algorithms or models, and for the joint development of advancedtechnologies. It takes advantage of many national and European service initiatives, for example DIAS(http://dias.space.noa.gr), SWACI (http://w3swaci.dlr.de), ESWUA (http://www.eswua.ingv.it/ingv), RWC-Warsaw(http://www.cbk.waw.pl/rwc), the COST Prompt Ionospheric Database http://www.wdc.rl.ac.uk/cgibin/digisondes/cost_database.pl, http://www.izmiran.ru/services, and others.Existing national capabilities are taken into account to develop synergies and avoid duplication. The enhancement of environment monitoring networks and associated instrumentation yields mutual advantages for European and regional services specialized for local user needs.It structurally increases the integration of limited-area services, and generates a platform employing the same approach to each task differing mostly in input and output data. In doing so it also provides a complementary description of the environmental state within issued information, as well as providing a platform for interaction among local end users, who define what kind of information they need, for system providers, who finalize thetools necessary to obtain required information, and for local service providers, who do the actual processing ofdata, tailoring it to specific users’ needs. Such an initiative creates a unique opportunity for small national servicesto consolidate their product design so that is no longer limited to their own activity, but can serve the wider European services.The development and improvement of techniques for mitigating ionospheric effects on radio systems by theCOST 296 Action prepared those services that implemented the new design techniques for the newly announced EU and ESA policy-Space Situation Awareness (SSA). COST 296 developments applied to nowcasting and forecasting services are an essential input to the Operational SSA Ionosphere. Sat, 01 Aug 2009 00:00:00 GMT http://hdl.handle.net/2122/5239 Titolo: Near-Earth space plasma modelling and forecasting<br/><br/>Autori: Strangeways, H. J.; School of Electronic and Electrical Engineering, University of Leeds, Leeds, UK; Kutiev, I.; Geophysical Institute, Bulgarian Academy of Sciences (BAS), Sofia, Bulgaria; Cander, L. R.; Rutherford Appleton Laboratory, Didcot, UK; Kouris, S.; Electrical and Computer Engineering Department, Aristotle University of Thessaloniki, Greece; Gherm, V.; Department of Radiophisics, University of St. Petersburg, Russian Federation; Marin, D.; University of Huelva, Huelva, Spain; De La Morena, B.; Atmospheric Sounding Station El Arenosillo, INTA, Huelva, Spain; Pryse, S. E.; Aberystwyth University, Aberystwyth, UK; Perrone, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Pietrella, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Stankov, S.; Royal Meteorological Institute, Brussels, Belgium; Tomasik, L.; Center for Space Research, Warsaw, Poland; Tulunay, E.; Middle East Technical University (METU), Ankara, Turkey; Tulunay, Y.; Middle East Technical University (METU), Ankara, Turkey; Zernov, N.; Department of Radiophisics, University of St. Petersburg, Russian Federation; Zolesi, B.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia<br/><br/>Abstract: In the frame of the European COST 296 project (Mitigation of Ionospheric Effects on Radio Systems, MIERS)in the Working Package 1.3, new ionospheric models, prediction and forecasting methods and programs as well as ionospheric imaging techniques have been developed. They include (i) topside ionosphere and meso-scale irregularity models, (ii) improved forecasting methods for real time forecasting and for prediction of foF2,M(3000)F2, MUF and TECs, including the use of new techniques such as Neurofuzzy, Nearest Neighbour, Cascade Modelling and Genetic Programming and (iii) improved dynamic high latitude ionosphere models through tomographic imaging and model validation. The success of the prediction algorithms and their improvement overexisting methods has been demonstrated by comparing predictions with later real data. The collaboration between different European partners (including interchange of data) has played a significant part in the development and validation of these new prediction and forecasting methods, programs and algorithms which can be applied to a variety of practical applications leading to improved mitigation of ionosphereic and space weather effects. Sat, 01 Aug 2009 00:00:00 GMT http://hdl.handle.net/2122/4825 Titolo: Stress interaction effect on the occurrence probability of characteristic earthquakes in Central Apennines<br/><br/>Autori: Console, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Murru, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Falcone, G.; Earth Science Department, Messina University; Catalli, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia<br/><br/>Abstract: 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. Tue, 19 Aug 2008 00:00:00 GMT http://hdl.handle.net/2122/4414 Titolo: Collaboration among COST actions. Ionosphere and space weather<br/><br/>Autori: Lilensten, J.; Laboratoire de Planétologie de Grenoble, OSUG-CNRS, France; Zolesi, B.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Belehaki, A.; Ionospheric Group, Institute for Space Applications and Remote Sensing, National Observatory of Athens, Metaxa and Vas. Pavlou, 15236 Palaia Penteli, Greece; Stanislawska, I.; Polish Academy of Sciences Space research center Bartycka 18 A 00 716 Warsaw Poland; Perrone, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia<br/><br/>Curatori: The COST 724 Members; various Universities and Institutes<br/><br/>Abstract: In this paper, we describe the collaboration between two COST actions: COST 724 devoted to space weather and COST 296 (formerly COST 271) devoted to the study of the ionosphere and its impact on communication and positionning. Several colleagues work in the two actions. This resulted in an important input provided by the COST 296 action to COST 724 based on the ionospheric models developed during the last COST actions (COST 238, 251, 271 and 296) for space weather applications. Tue, 01 Jan 2008 00:00:00 GMT http://hdl.handle.net/2122/4269 Titolo: Real time forecasts through an earthquake clustering model constrained by the rate-and-state constitutive law compared with a purely stochastic ETAS model<br/><br/>Autori: Console, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Murru, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Catalli, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Falcone, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia<br/><br/>Abstract: We propose an earthquake clustering model based on thepopular concept of epidemic models. In these models everyearthquake can be regarded as both triggered by previousevents and as a potential triggering event for subsequent earthquakes(Ogata 1988, 1998; Ogata and Zhuang 2006 and referencetherein; Console and Murru 2001; Console et al. 2003;Console et al. 2006a, 2006b; Helmstetter and Sornette 2002a,2002b, 2003 for reviews; and Vere-Jones 2006 for review on theuse of stochastic models for earthquake occurrence). The occurrence-rate density at any time and geographical location is computedby the contribution of every previous event using a kernelfunction that takes into proper account: (a) the magnitude ofthe triggering earthquake, (b) the spatial distance from the triggeringevent, and (c) the time interval between the triggeringevent and the instant considered for the computation. The magnitudedistribution adopted here is the Gutenberg-Richter law(Gutenberg and Richter 1944). The above-mentioned criteriaare implemented through the introduction of the rate-and-stateconstitutive law in a previously existing epidemic algorithm.The validity of the model can be tested in an exercise of realtimeforecast. Mon, 01 Jan 2007 00:00:00 GMT http://hdl.handle.net/2122/4075 Titolo: foF2 prediction in Rome observatory<br/><br/>Autori: Perrone, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Pietrella, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Zolesi, B.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Malagnini, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia<br/><br/>Curatori: U.R.S.I.; International Union of Radio Science<br/><br/>Abstract: A prediction procedure of the hourly values of the critical frequency of the F2 ionospheric layer, foF2, based on the local geomagnetic index ak, is presented. The geomagnetic index utilised is the time-weighted accumulation magnetic index ak(τ) based on recent past history of the index ak. It is utilised an empirical relationship between the log(NmF2(t)/ NmF2M), where NmF2(t) is the hourly maximum electron density at the F2 peak layer and NmF2M is its 'quiet' value, and the time weighted magnetic index. The prediction of foF2 is calculated during periods of severe magnetic activity in the current solar cycle 23 in Rome observatory. Thu, 07 Aug 2008 00:00:00 GMT