PROBABILISTIC SEISMIC HAZARD ASSESSMENT OF UDAYAPUR DISTRICT

Abstract

Probabilistic Seismic Hazard Assessment (PSHA) is procedure applied to access the seismic hazard of any location or area. Uncertainties associated with size, location and rate of recurrence of earthquake are identified and quantified to provide the idea about seismic hazard at the location. In this study PSHA is performed to access seismic hazard for Udayapur District. For the study earthquake catalogue were acquired from United States Geological Survey (USGS), International seismological Center (ISC), National Earthquake Monitoring & Research Center (NEMRC) and historical data were obtained from various sources. Five aerial Source Zones used are as provided by (Elliott et al., 2016). Declustering is done using algorithm explained by (Gardner & Knopoff, 1974) and completeness test is performed in accordance with Stepp, (1972). Five ground motion prediction equations, namely Youngs et al. (1997), Zhao et al. (2006), Lin & Lee, (2008), Abrahamson et al. (2016) and Montalva et al. (2017) are applied to compute Spectral Acceleration (Sa) and Peak Ground Acceleration (PGA) .Results are presented as PGA (estimated from averaging the result of five attenuation relationships) and Uniform Hazard Spectra at bedrock for 10% probability of exceedance in 50 years and 2% probability of exceedance in 50 years. Final results obtained after calculations are PGA value of 0.36g at bedrock for 10% probability of exceedance in 50 years and 0.69g at bedrock for 2% probability of exceedance in 50 years.This study is an attempt to determine site specific design ground motion parameters which can be used by structural engineers in earthquake resistant design in and around Udayapur District.