ATTENUATION RELATION FOR WEST EURASIA DETERMINED WITH RECENT NEAR-FAULT RECORDS FROM CALIFORNIA,JAPAN AND TURKEY |
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Authors: | YOSHIMITSU FUKUSHIMA CATHERINE BERGE-THIERRY PHILIPPE VOLANT DAPHNÉ-ANNE GRIOT-POMMERA FABRICE COTTON |
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Institution: | 1. Izumi Research Institute, Shimizu Corp. , Fukokuseimei bldg, 2-2-2, Uchisaiwai-cho, Chiyoda-ku, 1000011, Tokyo, Japan E-mail: yf@ori.shimz.co.jp;2. Institut de Radioprotection et de Süreté Nucléaire , BP 17, 92262 Fontenay-aux-Roses cedex, France;3. Hémisphères 1, Rue du Chateau, 92200 Neuilly sur Seine, France E-mail: d.pommera@hemispheres.fr;4. Laboratoire de Géophysique Interne et Techtonophysique , Université Joseph Fourier , BP 53 - 38041 Grenoble Cedex 9, France E-mail: Fabrice.Cotton@obs.ujf-grenoble.fr |
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Abstract: | Strong ground motion close to a fault can be expected to be very large, so its estimation is essential for human safetv. Although a few strong-motion data exist for the west Eurasian region, we proposed in a previous work Berge-Thierry et al., 2003] an attenuation relation for spectral acceleration using strong-motion data recorded in west Eurasia (mainly in Europe) and some in the western United States: this relationship was derived for the French Safety Rule, which is applied for seismic hazard assessment at nuclear power plants. In this study, we propose a constraining of the amplitude saturation term related to the proximity of the fault, and an adding of an amplitude saturation term in the regression model. We add, to the data-set previously used to derive the west Eurasian attenuation relationship strong-motions recorded during recent large earth-quakes: the 1995 Hyogo-ken Nanbu (Kobe) event in Japan and the 1999 Kocaeli (Izmit) event in Turkey. The regression analysis, adopted from Fukushima and Tanaka 1990], is non-linear, so an iterative procedure is applied. The determined regression coefficients lead to a prediction of a peak ground acceleration of about 0.7 g for soil site conditions at a fault distance of 0.5 km. The Q coefficient deduced, from the distance coefficient is in agreement with scattering Q models. The introduction of the saturation term leads to significantly lower predictions of average spectral accelerations at short distances as compared with using the Berge-Thierry et al. 2003] empirical model. |
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Keywords: | Attenuation relation response spectrum near-fault saturation west Eurasia |
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