Fault interaction for the Beni-Ilmane (east of Algeria) seismic sequence on May 2010
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ORIGINAL PAPER
Fault interaction for the Beni-Ilmane (east of Algeria) seismic sequence on May 2010 Hamoud Beldjoudi 1 Received: 19 May 2020 / Accepted: 2 September 2020 # Saudi Society for Geosciences 2020
Abstract This work is aimed at understanding the interaction between faults of three moderate events of the seismic sequence which occurred on May 2010 in the region of Beni-Ilmane which belongs to the Hodna-Biban domain (east of Algeria). This seismic sequence occurred on a complex faulted fold located in the Biban region in the southern part of the Tellian Atlas. The first shock occurred on May 14, 2010, at 12:29 GMT (Mw = 5.5) either on a dextral plane oriented [Strike, Dip, Rake: 254°, 74°, 175°] or on a sinistral plane oriented [Strike, Dip, Rake: 345, 85, 16]. Based on the stress change modeling, the fault plane with [Strike, Dip, Rake: 254°, 74°, 175°] is the one played for the first shock and starting the seismic sequence. I have also shown that the plane of the second shock which occurred on May 16 at 06:52 GMT (Mw = 5.1) oriented [Strike, Dip, Rake: 250°, 55°, 120°] is loaded by the first shock (Coulomb stress changes = 0.19 bar). The third shock occurred on May 23 at 13:28 GMT (Mw = 5.2) with plane oriented [Strike, Dip, Rake: 12°, 57°, 12°] was loaded by the two previous shocks (Coulomb stress changes = 0.04 bar). I have correlated aftershocks occurred during this seismic sequence with Coulomb stress changes modeling taking into account the contribution of the regional stress tensor shows that the greatest number of aftershocks is located in positive areas of total Coulomb stress changes with a percentage that exceeds 65%. The best results are obtained for thrust optimal planes oriented NE-SW. Keywords Coulomb stress change . Focal mechanism . Beni-Ilmane . Algeria . Regional stress
Introduction The 2010 Beni-Ilmane seismic sequence occurred on a complex faulted fold in the Biban region in the southern part of the Tellian Atlas (Fig. 1a, b). The region is bounded to the south by the northern front of the Hodna basin and to the north by the Soummam River valley. The epicentral area of the BeniIlmane seismic sequence is located at the boundary of two distinct geological domains: the Alpine Mountains and the Tellian Sub-Bibanique nappe in the north and the preAtlasic domain in the south (Yelles-Chaouche et al. 2014 ; Beldjoudi et al. 2016). The seismic sequence hits the BeniIlmane region between May 14 and 23, 2010. Three moderate This article is part of the Topical Collection on Seismic Hazard and Risk in Africa * Hamoud Beldjoudi [email protected] 1
Research Centre of Astronomy Astrophysics and Geophysics (CRAAG), Algiers, Algeria
shocks and 1431 aftershocks were recorded and located until May 31 (Table 1). The first shock with a moment magnitude of 5.5 Mw and seismic moment of 1.8 × 1017 Nm (Fig. 1c) occurred either on a dextral plane oriented [Strike1, Dip1, Rake1: 254°, 74°, 175°] or on sinistral plane oriented [Strike2, Dip2, Rake2: 345, 85, 16]. The second shock hit the region wi
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