Gis based seismic damage asssessment: a case study on Rajshahi city

Abstract

For accomplishing comprehensive regional seismic damage assessment, Geographical Information System (GIS) provides a perfect environment, GIS has the capability to store, manipulate, analyze and display the large amount of required spatial and tabular data. This study intends to carry out regional seismIc damage assessment for the Rajshahi City using geographic Information system. where reflection of ground shaking and the secondary site attnbutes of soil amplificalion and liquefaclion are the salient features The melhod to combine the different hazards is based on a weighted average applORch A soil database from 50 boreholes was used to develop site amplification and soil liquefaction potential maps ufthe study area. Bolh of these site effects are integrated in Geographical Information System platfonn for combined hazard assessment, Three past historical earthquakes were assessed as scenario events namely the 1885 ~engal earthquake, the 1897 Greallndian earthquake and the 1930 Dhubri earthquake, Intensily value obtained for these events is' calibrated against attenuation laws to check the applicability ofthe laws for the study. Finally, the Great Indian Earthquake of 1897, with the attenuation law of McGuire (1978) was chosen as the scenario earthquake. as it shows highest bed lOck PGA (0,06340) PGA value is converted into },ill] values to integrate the effect of site amplification as well as liquefaction and then combined hazard map is proposed for this study area, Only for ground shaking, approximately II percent buildings are ~1;imated to be damaged, Again for ground shaking and liquefaction, approximately 15 percent buildings are estimated to be damaged Some major critical facilities are idelllified that are the most vulnerable as they fall under VIIl-MM]! EMS Intensity hazard zone. Based on soil (natural) frequency some zones are suggested for building height restrictions using thumb rules, According to soil liquefaction analysis particular zones are identified where groL1ndimprovement is suggested,