On the GIS-based Seismic Risk Maps of Jablah City, Syria

Seismic risk assessment is a necessary study to mitigate future earthquake damage in urban area. Jablah city is an old coastal city in Syria; it had been affected by many historical earthquakes, and it has not been studied seismically yet. The seismic database in National Earthquake Center in Syria was used to calculate seismic hazard maps of the study area. These maps indicate that the values of the ground acceleration are increasing towards the north and southeast of the Jablah city. Field work on soil shows that dominant period values range from 0.34 to 2.5 seconds, and amplification factor values from 1.1 to 3.7. The period of free vibration of the buildings varied from 0.09 to 0.45 seconds for the selected buildings. To assess the current status of the buildings, an evaluation form of vulnerability has been prepared. As a result, the vulnerability coefficient of the studied buildings to seismic forces ranged from 0.3 to 0.6. To obtain seismic risk maps, GIS program was used to process multiple layers such as seismic hazard map, dominant period, amplification factor of soil, free vibration period of buildings and assessment of their current status. The results show that many crowded neighborhoods in Jablah city are located in high seismic risk areas where tall and important buildings are located. This confirms that the high potential of human and economic losses concentrated in the city center.