Earth-printshttps://www.earth-prints.orgThe DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Sun, 08 Sep 2024 07:04:36 GMT2024-09-08T07:04:36Z5021Stress interaction effect on the occurrence probability of characteristic earthquakes in Central Apennineshttp://hdl.handle.net/2122/4825Title: Stress interaction effect on the occurrence probability of characteristic earthquakes in Central Apennines
Authors: Console, R.; Murru, M.; Falcone, G.; Catalli, F.
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 GMThttp://hdl.handle.net/2122/48252008-08-19T00:00:00ZReal time earthquake forecasting in Italyhttp://hdl.handle.net/2122/4826Title: Real time earthquake forecasting in Italy
Authors: Murru, M.; Console, R.; Falcone, G.
Abstract: We have applied an earthquake clustering epidemic model to real time data at the Italian Earthquake Data Center operated by the Istituto Nazionale di Geofisica e Vulcanologia (INGV) for short-term forecasting of moderate and large earthquakes in Italy. In this epidemic-type model every earthquake is regarded, at the same time, as being triggered by previous events and triggering following earthquakes. The model uses earthquake data only, with no explicit use of tectonic, geologic, or geodetic information. The forecasts are displayed as time-dependent maps showing both the expected rate density of Ml ≥ 4.0 earthquakes and the probability of ground shaking exceeding Modified Mercalli Intensity VI (PGA ≥ 0.01 g) in an area of 100 × 100 km2 around the zone of maximum expected rate density in the following 24 h. For testing purposes, the overall probability of occurrence of an Ml ≥ 4.5 earthquake in the same area of 100 × 100 km2 is also estimated. The whole procedure is tested in real time, for internal use only, at the INGV Earthquake Data Center.
Forecast verification procedures have been carried out in forward-retrospective way on the 2006–2007 INGV data set, making use of statistical tools as the Relative Operating Characteristics (ROC) diagrams. These procedures show that the clustering epidemic model performs up to several hundred times better than a simple random forecasting hypothesis. The seismic hazard modeling approach so developed, after a suitable period of testing and refinement, is expected to provide a useful contribution to real time earthquake hazard assessment, even with a possible practical application for decision making and public information.
Thu, 01 Jan 2009 00:00:00 GMThttp://hdl.handle.net/2122/48262009-01-01T00:00:00Z