Seismic damage assessment using RADIUS and GIS: A case study of Sylhet City, Bangladesh

Seismic risk of urban areas around the world is a major concern to stakeholders due to the potential losses of lives and extensive damage to infrastructure that can occur following an earthquake. As risk mitigation resources are limited, a method for assessing risk and prioritizing structures for seismic retrofit at a city or regional scale is required. Scenario-based seismic damage prediction can be used by decision-makers for identifying the riskiest structures that can be prioritized for risk mitigation to optimize the use of available resources. In this case study, for the first time, seismic damage estimation is performed for Sylhet City Corporation (SCC), Bangladesh by integrating Risk Assessment tools for Diagnosis of Urban areas against Seismic disasters (RADIUS) and Geophysical Information System (GIS). Building structures, infrastructure, and soil type information for SCC from a recent study performed by the local government under the framework of the Comprehensive Disaster Management Program (CDMP) are used. The building inventory and other information in the study area are divided into 1.0 × 1.0 square km grids and the information is mapped into RADIUS. Two scenario earthquakes are chosen to perform damage estimation of existing buildings and infrastructures. The study reveals that the two scenario earthquakes (M w 8.0 from Dauki Fault and M w 7.6 from Plate Boundary Fault 2) can result in extensive damage and a high number of casualties in the SCC area. The integrated GIS and RADIUS approach provides useful information for decision making in the seismic risk mitigation plan of the city.