The Beni Haoua, Algeria, Mw 4.9 earthquake: source parameters, engineering, and seismotectonic implications

Autor: Farida Ousadou, Khadidja Abbes, Djillali Bouziane, Catherine Dorbath, Nassima Benkaci, Said Larbes, Mohamed Djeddi, Louis Dorbath, Said Maouche, A. Slimani
Rok vydání: 2015
Předmět:
Zdroj: Journal of Seismology. 20:655-667
ISSN: 1573-157X
1383-4649
Popis: A moderate Mw 4.9 earthquake struck the Beni Haoua (Algeria) coastal area on April 25, 2012. The mainshock was largely recorded by the accelerograph network of the Centre National de Recherche Appliquee en Genie Parasismique (CGS). The same day the earthquake occurred, eight mobile short period stations were deployed through the epicentral area. In this study, we use accelerogram and seismogram data recorded by these two networks. We combined the focal mechanism built from the first motion of P waves and from waveform inversion, and the distribution of aftershocks to well constrain the source parameters. The mainshock is located with a shallow focal depth, ∼9 km, and the focal mechanism shows a nearly pure left lateral strike slip motion, with total seismic moment of 2.8 × 1016 N.m (Mw = 4.9). The aftershocks mainly cluster on a narrow NS strip, starting at the coast up to 3–4 km inland. This cluster, almost vertical, is concentrated between 6 and 10 km depth. The second part of this work concerns the damage distribution and estimated intensity in the epicentral area. The damage distribution is discussed in connection with the observed maximum strong motion. The acceleration response spectrum with 5 % damping of the mainshock and aftershocks give the maximum amplitude in high frequency which directly affects the performance of the high-frequency structures. Finally, we tie this earthquake with the seismotectonic of the region, leading to conclude that it occurred on a N–S transform zone between two major compressional fault zones oriented NE–SW.
Databáze: OpenAIRE
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