A comparative study of different PGA attenuation and error models: Case of 1999 Chi-Chi earthquake

摘要

In order to evaluate the horizontal peak ground acceleration (HPGA) during earthquakes, the author studies the respective efficiency of two existing attenuation models [Mebarki, A., 2003a, Risques sismiques: aleas, vulnerabilite et aide 6 la decision par cartes SIG. Proceedings of International Conference on "Risks, Vulnerability and Reliability in Construction. Towards a reduction of disasters". ISBN: 9961-891-01-5, pp. 82-97. Algiers, October 11-12, Mebarki, A., 2003b. Proposal of a parametric attenuation model and comparison with some worldwide earthquakes. VII degrees Congreso Venezolano de Sismologia y Ingenieria Sismica, Barquisimeto, Venezuela. November 12-13, (CD-ROM), Mebarki A., 2004. Modele d'attenuation sismique: prediction probabiliste des pics d'acceleration, RFGC-Revue Francaise de Genie Civil, Hermes Ed., 8 (9-10), 10711086]. A comparative study of their performances is done in the case of 1999 Chi-Chi earthquake (Taiwan). The reported PGA (Peak Ground Accelerations) values correspond to hypocentral distances ranging from 15 up to 180 km with observed acceleration peaks ranging from (0.04 g) up to (1.16 g). The author considers two kinds of probabilistic distributions for the error model in order to describe the uncertainty and the variability that affect the values of the PGA: a Gamma distribution and a Log-normal distribution. The adopted error models assume that the variability of the PGA is such that its coefficient of variation is equal to 55% [Mebarki, A., 2003a. Risques sismiques: aleas, vulnerabilite et aide A la decision par caries SIG. Proceedings of International Conference on "Risks, Vulnerability and Reliability in Construction. Towards a reduction of disasters". ISBN: 996-1891-01-5, pp. 82-97. Algiers, October 11-12, Mebarki, A., 2003b. Proposal of a parametric attenuation model and comparison with some worldwide earthquakes. VIII degrees Congreso Venezolano de Sismologia y Ingenieria Sismica, Barquisimeto, Venezuela. November 12-13, (CD-ROM), Mebarki, A., 2004. Modle d'attenuation sismique: prediction probabiliste des pics d'acceleration, RFGC-Revue Francaise de Genie Civil, Hernmes Ed., 8 (9-10), 1071-1086]. The obtained results show that both attenuation models provide adequate values of the PGA when a Gamma distribution is adopted for the error model. The attenuation models efficiency decreases slightly when a Log-normal distribution is adopted for the error model.