SEISMIC HAZARD, VULNERABILITY AND RISK ANALYSIS FOR THE ROORKEE CITY AND ITS VICINITY

Abstract

Earthquake are one of nature greatest hazard to life’s and property which could cause intense shaking at the earth’s surface and have potential to cause huge socio-economic losses. Rapid growth of population, urbanization and poor construction practices in high risk zones level of risk will have a significant impact, the assessment of earthquake’s risk will help to visualize the consequences and potential socio-economic losses and helps to decide what to do. In quantitative risk assessment, risk is expressed as a function of the hazard, the elements at risk and the vulnerability. From a natural sciences perspective, vulnerability is defined as the expected degree of loss for an element at risk as a consequence of a certain event. In this study, DSHA of Roorkee city, city of Haridwar (Uttarakhand) forms a part of the most severe seismic zone in the country. As per seismic zoning map of India (IS: 1893 Part-1, 2016), it is lies zone IV which is high. Considering whole earthquake data and data within completeness period seismicity parameters has been estimated. The study area covers (29.83°N-29.89°N, latitudes77.86 °E-77.93°E longitudes) within 300km circular distance from the political boundary of the district. It lies in the north part of the India which is considered as one of the two most active plate tectonic regions in the world. Because of the increasing population and rapid growth of unplanned urban infrastructures that inhabits this region, PGA value is calculated using the Abrahamson and silva 2008 NGA model for different type of faults (thrust and neotectonic) and different values of MMAX, shortest distance and Depth to top of coseismic rupture (Ztor). This study also estimates earthquake risk in terms of socio-economic losses using an open software toll named Seis-VARA Spectrum considering computed PGA value at Roorkee city as a scenario event potential loss has been estimated. The results of loss assessment indicate that the study area could face significant losses and future repeat of these past earthquakes would be disastrous.