Scenario Based Regional Seismic Loss Assessment: A Case study on South West district of Delhi

Regional Seismic Loss Assessment (RSLA) studies the effects of earthquakes on society on a regional scale. It is necessary to evaluate the performance of buildings during strong earthquakes, which depends mainly on the ground motion characteristics, energy absorption, and dissipation capacity of structures in a region. In the present study, scenario-based loss assessment is considered for the Southwest district of Delhi, which has varied categories of both rural and urban regions with both commercial and residential buildings. Critical lifeline infrastructures, such as the International Airport of National Capital Territory (NCT) Delhi, are also present in the selected region. The southwest district lies in the active seismic region surrounded by the Sohna Fault, Dehradun Subsurface Fault (MDSSF), and Delhi Sargodha Ridge (DSR), which are the primary sources of potential seismic hazards in the region. Preliminary building data were collected for the district, including material characteristics, type of structure, area of the building, number of floors, and height of the building. The ground motion characterization of the site was performed using three universal Ground Motion Prediction Equations (GMPEs). Geotechnical parameters such as shear wave velocity (Vs 30) values for the site of interest were considered as per the microzonation studies of the region. In this study, structural analysis, building damage, and loss assessments were conducted for the region. Sensitivity analysis of the four major input parameters was performed to evaluate the contribution and uncertainty of the assessment. It is observed that the majority of buildings have masonry walls, non-engineering materials used as roofing materials, and lack proper lateral load-resisting systems, thus leading to low seismic resilience. The region is also expected to have total injuries between 5.2 lakhs and 5.7 lakhs, which is more than 20 percent of the total population. This study aims to create awareness among engineers, policymakers, and residents about the potential seismic risk of the area and would also help in designing proper preparedness and mitigation measures for the region.