Presentation on theme: "SISMA: Workshop finaleASI, 4 maggio 2011 Il Progetto Progetto SISMA: razionale, attività e principali risultati Roberto Sabadini Università degli Studi."— Presentation transcript:
SISMA: Workshop finaleASI, 4 maggio 2011 Il Progetto Progetto SISMA: razionale, attività e principali risultati Roberto Sabadini Università degli Studi di Milano
SISMA: Workshop finaleASI, 4 maggio 2011 SISMA new approach towards the understanding of earthquake generation and seismic hazard mitigation builds over three major concepts: taking advantage of the new generation of DINSAR and GPS deformation data at the Earths surface in conjunction with seismic flow monitoring which in turn allows us building an integrated geophysical, geodetic and seismological scheme to disclose stress build up within the gouge of sesmic active faults for a deterministic approach of earthquake cycle description which in turn allows us overcoming the obvious shortcomings of the old approach to seismic hazard mitigation based on a purely probabilistic approach
M5.5+M6.0+M6.5+ CN algorithm Times of Increased Probability for the occurrence of events with M>Mo within the monitored regions Monitored region Alerted region M8S algorithm
SISMA: Workshop finaleASI, 4 maggio 2011 Geodetic and seismic integration: IBAY map Red = geodetic anomalies plus seismic alert Green = neither geodetic anomalies nor seismic alert Yellow = geodetic anomalies Orange = seismic alert The numbers in the red zones give the relative alert value.
SISMA: Workshop finaleASI, 4 maggio 2011 Local ground shaking scenario for the Gubbio site Ground motion scenarios at local scale Detailed scenarios of ground motion, including site effects (2D sections describing the mechanical properties of the sites), are defined at the local scale for the alerted faults. Synthetic seismograms Spectral amplifications 2D laterally heterogeneous local profile
SISMA: Workshop finaleASI, 4 maggio 2011 Conclusions Although the seismic classification of the Italian territory has been recently revised, the evaluation of seismic hazard continue to be based on the traditional probabilistic approach, i.e. on the probabilistic analysis of earthquake catalogue and of ground motion information, retrieved by macroseismic observations and instrumental recordings, that may lead to severe underestimations of seismic hazard. Recently this approach showed its limitation in providing a reliable seismic hazard assessment, possibly due to the insufficient information about historical seismicity, which can introduce relevant errors in the purely statistical approach mainly based on the seismic history.