Pre-Seismic Assessing Hazard: Examples of Northern Algeria

The study aims to describe the potential seismic tectonic structures and the seismic hazard mapping. The pre-seismic assessing is initiated for two regions belonging to Algerian Maghrebides chain, Constantine area in the East and Relizane area in the West. It is based on the inventory of mainly tectonic structures reported in the bibliography as being active within a radius of 50 kilometers of the both regions. For this purpose, a map of the principal neotectonic structures is established on basis of morphotectonic and structural interpretations of the zones which reveal indices of active tectonics. Then, seismotectonic analysis is carried out by correlation between tectonic structures and historical seismicity. A preliminary seismotectonic zonation is established. The seismic zonation map enlightens seismic source zones and seismic lines; the identified faults and suspected active faults affecting the both areas aremodeled as source lines. And the areasmarked by diffuse seismicity, are modeled as sources zones; therefore, three seismotectonic provinces have been defined. This preliminary seismotectonic zonation will direct the field work and also the management of data in GIS for quick response to any improvement in the assessment.