SEISMIC HAZARD EVALUATION FOR MICROZONATION

Abstract

Reduction of seismic disasters in urban areas is one of the challenging problems in the sustainable development of modem. society. With the rapid development of urbanization and population, this problem becomes more and more important. Seismic zonation study of different areas is attracting a steadily increasing attention among experts and the public. With the development of economy, earthquake-induced disasters such as landslides, land subsidence, soil liquefaction, and ground fissures, among others, cause am increasing loss of property. To focus on the up-to-date development and outstanding problems in the mitigation of seismic disasters planning of the area is basic need. This study is an attempt to estimate the seismic hazard in northern part of India adjoining Uttaranchal. This particular area has been selected due to its high seismicity. The presence of many seismogenic sources in the area shows the seismic hazard potential present in this region. The factors contributing to the earthquakes and different methods used to estimating seismic hazard have been studied. The studies related to the tectonics, seismicity and geology are made and a methodology is developed to integrate the technology of geographic information (GIS) system in evaluating the seismic hazard assessment. An interactive programme in Visual Basic, the macro language of ARCGIS 8.1 is developed to carry out various steps involved in deterministic approach of seismic hazard assessment. To make the prgramme user friendly and ready to use it is customized in the form of a dynamic tool, "Seismic Hazard Assessment Tool' with GIS software. The results have been presented in the form of expected peak ground accelerations in the region for maximum considered earthquake from the seismogenic sources. The isoacceleration contours for peak ground horizontal acceleration are presented in form of maps drawn for different sources. The combined result of the all sources is presented as a final map, which may be used for zonation and further used for microzonation studies.