Determination of Source Parameters of The Beni-Ilmène (Algeria) Earthquake Sequence (Mw=5.5, 5.3, and 5.3)

A moderate earthquake with moment magnitude Mw=5.5 hit the Subbibanique region in the East of Algeria at the locality of Beni-Ilmène on 14/05/2010 at 12h29mn(GMT).The earthquake was located by the CRAAG at latitude 35.99°N and longitude 4.19°E, the depth was 6 km.The Focal Mechanism(FM) of the seismic source obtained by waveform modeling (near-field) shows left-lateral strike-slip for the nodal plane oriented N345° and right-lateral strike-slip for the second nodal plane oriented N254°. A second shock stroke on 16 May 2010 with Mw=5.3. It is localized 9 km SW of the first shock at latitude 35.96°N, longitude 4.06°E and 5 km of depth. The FM obtained by waveform modeling shows reverse faulting with nodal planes oriented NE-SW. A third shock hit on 23 may 2010 with Mw=5.3, localized 7 km at the south of the first shock at the latitude 35.93° N, longitude 4.12° N and 6 km of depth. The FM obtained shows a left-lateral strike-slip plane oriented N355° and a right-lateral plane oriented N85° similar to that of the first shock. Geologic and sismotectonic analysis lead us to conclude that the fault plane of the first shock is oriented NNW–SSE and other shocks were generated by separate faults.