GIS and Remote Sensing

The seismic vulnerability of an urban area is of a great deal for local authorities especially those facing earthquakes. So, it is important to have an efficient tool to assess the vulnerability of existing buildings. Blida is located in the north part of Algeria, an area prone to seismicity. It is classified zone III according to the Algerian Seismic Code (RPA99 version 2003). The town is among the oldest cities in the north. Build especially during the colonial period, Blida is characterized by vulnerable urban conditions with dense buildings and narrow roads. Using geographic information systems (GIS), the seismic vulnerability of Blida is assessed. First the vulnerability indexes of buildings are calculated, then making seismic scenarios. Damage rates are determined taking into account the seismotectonic aspect of the region and the vulnerability curves of structures commonly found in Blida. The rates of damage caused by the earthquake considered in the scenario highlighted the high vulnerability of Blida. These results can allow elaborating strategic countermeasure plans for the earthquake risk mitigation in the city.