ASSESSMENT OF GEOTECHNICAL SEISMIC HAZARD OF THE DHAMAR CITY, YEMEN

Abstract

The objective of this paper is to asses s and present the geotechnical seismic hazard in the Dhmarar city, Yemen. During the present study assessment for the geotechnical seismic hazard was carried out in an area of 100 km radius around Dhamar city. Based on the Geotechnical data obtained for th is study, Seismotectonic maps are constructed showing the major lineaments to trend in NW - SE, NE - SW and SWW - NEE directions that attribute to the general directions of the axial of the Red Sea and the Gulf of Aden. The earthquake catalogue of the region fac ilitated the classification of seismicity of the region into three major seismic periods. The b value is classified as low and is the characteristic of the continental rift zone that corroborates well with the geological evolution of the study area. Isointensity zoning and PGA maps with two epicentral distances of zero and 50 km were constructed. Th e Isointensity maps indicated that the intensity of the entire study region ranges from II to VIII on MMI scale. Micro level study carried out in the immediate vicinity of Dhamar city indicates the region to be slightly hazardous whose intensity ranges fro m II to III on MMI scale. The PGA values for the region and the area under investigation vary from zero to 500 and 20 to 180 cm/sec 2 respectively. Based on the geotechnical field evidences and statistical data, the relation between seismicity, volcanicity and thermal springs are strong.