Etude de la microsismicite de la region de kherrata

Abstract

The Babors region has experienced several earthquakes of low to moderate magnitude. Seismic activity is fairly continuous, with numerous seismic events recorded in this region annually. The Babors are affected by several faults that formed during the compressional phases of the Alpine orogeny—a result of the convergence between the African and Eurasian plates. Among these is the Kherrata fault, described by Rothé (1950) following the earthquake of February 17, 1949; it is likely responsible for the majority of the seismic activity in the region. The Lâalam earthquake of March 20, 2006, occurred in this area. To monitor aftershock activity, a temporary seismic network was deployed in the region for 16 days. The aftershocks were generated by a new fault, indicating that the geometry of the primary fault system in the Babors region is complex. This event appears to have originated on a north-south-trending relay segment situated between the eastern and western sections of the Lesser Kabylia (Petite Kabylie) massif. Seismic activity remained intense throughout 2007 in the vicinity of Kherrata. Furthermore, seismogenic zones have emerged south of Sétif—specifically, a major NW-SE-trending fault system that marks the boundary between the High Plateaus (Hauts Plateaux) and the Constantine High Plains (Hauts Plaines constantinoises)—as well as in the area east of Sétif. A better understanding of the spatial distribution of seismicity in the study area is essential for more accurately assessing seismic hazard, which in turn will help mitigate seismic risk. Keywords: Seismicity, Tell Atlas, fault, Kherrata, seismotectonics, the Babors.