Connotea
CiteULike
del.ico.us
BibSonomyAbstract
GEOPHYSICAL RESEARCH LETTERS,
VOL. 31,
L19606,
4 PP., 2004
doi:10.1029/2004GL020586
The 21 May 2003 Zemmouri (Algeria) earthquake Mw 6.8: Relocation and aftershock sequence analysis
Faculty of Earth Sciences, Université des Sciences et de la Technologie Houari Boumediene, Algiers, Algeria
Centre du Génie Parasismique, Algiers, Algeria
Ecole et Observatoire des Sciences de la Terre and Institut de Recherche pour le Développement, UMR 5563, Laboratoire des Mécanismes de Transfert en Géologie (LMTG), Strasbourg, France
Centre de Recherche en Astronomie, Astrophysique et Géophysique, Algiers, Algeria
Structure and Non-Linear Dynamics of the Earth (SAND) Group, Abdus Salem International Centre for Theoretical Physics (ICTP), Trieste, Italy
UMR 7516, Institut de Physique du Globe, Strasbourg, France
Centre de Recherche en Astronomie, Astrophysique et Géophysique, Algiers, Algeria
Centre du Génie Parasismique, Algiers, Algeria
UMR 7516, Institut de Physique du Globe, Strasbourg, France
Centre du Génie Parasismique, Algiers, Algeria
UMR 7516, Institut de Physique du Globe, Strasbourg, France
Centre de Recherche en Astronomie, Astrophysique et Géophysique, Algiers, Algeria
Centre de Recherche en Astronomie, Astrophysique et Géophysique, Algiers, Algeria
Centre du Génie Parasismique, Algiers, Algeria
Centre de Recherche en Astronomie, Astrophysique et Géophysique, Algiers, Algeria
Structure and Non-Linear Dynamics of the Earth (SAND) Group, Abdus Salem International Centre for Theoretical Physics (ICTP), Trieste, Italy
Centre du Génie Parasismique, Algiers, Algeria
Centre de Recherche en Astronomie, Astrophysique et Géophysique, Algiers, Algeria
A strong earthquake (Mw 6.8) struck the coastal region east of Algiers and the Tell Atlas of Algeria on 21 May, 2003 and was responsible of severe damage and about 2400 casualties. The coastal mainshock was followed by a large number of aftershocks, the largest reaching Mw 5.8 on 27 May 2003. We study the mainshock, first major aftershocks and about 900 events recorded by temporary seismic stations using master-event approach and double-difference (DD) methods. Although the seismic station array has a large gap coverage, the DD algorithm provides with an accurate aftershocks location. The mainshock hypocenter relocation is determined using three major aftershocks (5.0 ≤ Mw ≤ 5.8) chosen as master events. The new mainshock location shifted on the coastline (36.83N, 3.65E) at 8–10 km depth. Seismic events extend to about 16-km-depth and form a N 55°–60°E trending and 45°–55°SE dipping fault geometry. Up to now, it is the unique among the recently studied seismic events of the Tell Atlas of Algeria. Mainshock and aftershocks relocation, the thrust focal mechanism (Harvard CMT: N 57°, 44°SE dip, 71 rake) and the seismic moment 2.86 1019 Nm, infer a 50-km-long fault rupture that may appear at the sea bottom at 6 to 12 km offshore north of the coastline. The Zemmouri earthquake occurred along the complex thrust-and-fold system of the Tell Atlas and provides with new constraints on the earthquake hazard evaluation in northern Algeria.
Received 26 May 2004; accepted 19 August 2004; published 8 October 2004.
Citation: (2004), The 21 May 2003 Zemmouri (Algeria) earthquake Mw 6.8: Relocation and aftershock sequence analysis, Geophys. Res. Lett., 31, L19606, doi:10.1029/2004GL020586.
Cited By