A Catalog of Main Moroccan Earthquakes from 1045 to 2005

Abstract

A homogeneous and reliable earthquake catalog is highly desirable in seismic hazard studies. This work, the compilation of as complete and homogeneous a main Moroccan earthquake catalog as possible, has been developed in the context of a project to compute the probabilistic seismic hazard in this region. The result shown here is the outcome of fruitful teamwork among several Spanish, Moroccan, and Algerian institutions. Previous earthquake catalogs that specifically cover this region ( e.g. Tadili and Ramdani 1983; Cherkaoui 1986; Benouar 1994), although employed in seismic hazard assessments (Benouar et al. 1996; Jimenez et al. 1999), did not span the desirable time interval. Many of them did not include pre-1900 events, i.e. , large shocks that occurred in the historical period. Moreover, a real magnitude unification process was not performed. Our initial goal was to catalog all known events from every available published source for the area between 27° to 37°N and 15°W to 1°E, including the southernmost part of Spain and Portugal and the western region of Algeria. We obtained a uniform catalog, using for this purpose several empirical relationships among reported magnitudes, macroseismic intensity, and moment magnitude. Finally, we removed all dependent events, as well as earthquakes with magnitudes smaller than M W 3.0. The final catalog covers the period from 1045 to 2005 and includes 1,739 mainshocks. It can be downloaded in a self-explanatory Excel file from the University of Jaen Web site at http://www.ujaen.es/investiga/rnm217/moroccan_catalog.xls. Tabulated data include agency, origin time, epicenter (coordinates, depth, and location), reported magnitude or maximum intensity and unified magnitude. The analyzed region (figure 1) includes the southernmost part of the Iberian Peninsula, the western portion of the Mediterranean Sea (Alboran Sea), the central-eastern area of the Atlantic Ocean, and the northwestern area of Africa (basically Morocco), located in the …