The 22 February 2014 Mw 4.1 Bordj-Menaiel Earthquake, Near Boumerdes-Zemmouri, North-Central Algeria

Abstract

A number of destructive earthquakes have occurred in the region of Algiers, the capital of Algeria. Two well‐known historical earthquakes were recorded in 1365 and 1716 (Harbi et al. , 2004). A more recent one, the 2003 M w 6.9 Boumerdes earthquake (also called the Zemmouri earthquake), took place in the Boumerdes district (Fig. 1), about 50 km east of Algiers (Yelles‐Chaouche et al. , 2003). The Boumerdes earthquake occurred on a blind‐thrust fault offshore from the Algerian coast. The rupture was along a northeast–southwest‐striking fault plane, although the precise fault trace was unknown. During this earthquake, an average value of 55 cm of uplift of the shoreline was observed (Meghraoui et al. , 2004), consistent with the thrust focal mechanism, at least in the high‐slip region on the fault plane (Semmane et al. , 2005). Figure 1. The studied area and location of stations that recorded the earthquake used in this study (closed triangles are broadband stations and open triangles are one‐component short‐period stations). Dots show the seismic epicenters from 1992 to March 2014; the 2003 Boumerdes epicenter is represented by the black star, and the Bordj‐Menaiel earthquake is represented by the white star. The black lines are active faults mapped by Guemache (2010). The inset shows the basement in the region in gray. The locations of the numbered blocks 1 and 2 coincide with the two asperities found in the slip distribution models and also with the uplift zones (two thick lines on the coast). More recently, in the same district (Boumerdes), an earthquake of moment magnitude M w 4.1 ( M d 4.3) occurred on 22 February 2014 at 20:30 local time, 12 km southeast of the epicenter of the 2003 Boumerdes earthquake, and at a depth of 7–11 km. The epicenter was located 5 km northeast of the central part of the town of Bordj‐Menaiel and …