HR: 0800h
AN: S11A-0270    [Abstracts]
TI: Study of the Intensity and Acceleration Attenuations in Spain and Their Impact in the Seismic Hazard Determination
AU: * Mezcua, J A
EM: jmezcua@fomento.es
AF: Instituto Geografico Nacional, General Ibanez de Ibero 3, Madrid, 28003, Spain
AU: * Mezcua, J A
EM: jmezcua@fomento.es
AF: Universidad Politécnica de Madrid, Campus Sur, Aut. Valencia 7.5, Madrid, 28031, Spain
AU: Garcia Blanco, R M
EM: ro_gar@topografia.upm.es
AF: Universidad Politécnica de Madrid, Campus Sur, Aut. Valencia 7.5, Madrid, 28031, Spain
AU: Rueda, J J
EM: jjrueda@fomento.es
AF: Instituto Geografico Nacional, General Ibanez de Ibero 3, Madrid, 28003, Spain
AB: In the seismic hazard determination, one of the most crucial steps is the selection of an estimation of the ground motion according to the size and distance of the selected event. Up to now, we in Spain used a set of different attenuation laws on intensity values, depending of the tectonic area in which the event is included. Those attenuation relationships have been obtained using different isoseismal maps for the Iberian Peninsula. However if we perform an analysis of the isoseismal maps used in the different studies following the Bakun & Wenthworth (1999) technique we found a similar coefficient and no regionalization can be established as was done systematically by different authors. Moreover, the range of Q values estimates for the different areas also confirms this conclusion. As in the last years a considerable number of strong ground motion data were recorded in Spain, we obtained a new PGA attenuation relationship for the territory. The relationship is obtained with 273 acceleration values of events of moment magnitude M greater than 3 in the epicentral distance range between 5 and 100 kilometers and is compared with other relations for similar tectonic environments. Finally, we have calculated the seismic hazard of Spain using both types of data, intensity values and intensity attenuation and magnitude values and the acceleration attenuation obtained. A description of the impact of using those data is performed, showing an appreciable increase near 10 % of the hazard values in the southwestern part of the Iberian Peninsula using the new acceleration attenuation obtained.
DE: 7212 Earthquake ground motions and engineering seismology
SC: Seismology [S]
MN: 2007 Fall Meeting