Abstract
Abstract. In this work an attempt has been made to evaluate the seismic hazard of South India (8.0° N–20° N; 72° E–88° E) based on the probabilistic seismic hazard analysis (PSHA). The earthquake data obtained from different sources were declustered to remove the dependent events. A total of 598 earthquakes of moment magnitude 4 and above were obtained from the study area after declustering, and were considered for further hazard analysis. The seismotectonic map of the study area was prepared by considering the faults, lineaments and the shear zones in the study area which are associated with earthquakes of magnitude 4 and above. For assessing the seismic hazard, the study area was divided into small grids of size 0.1°×0.1°, and the hazard parameters were calculated at the centre of each of these grid cells by considering all the seismic sources with in a radius of 300 km. Rock level peak horizontal acceleration (PHA) and spectral acceleration (SA) values at 1 s corresponding to 10% and 2% probability of exceedance in 50 years have been calculated for all the grid points. The contour maps showing the spatial variation of these values are presented here. Uniform hazard response spectrum (UHRS) at rock level for 5% damping and 10% and 2% probability of exceedance in 50 years were also developed for all the grid points. The peak ground acceleration (PGA) at surface level was calculated for the entire South India for four different site classes. These values can be used to find the PGA values at any site in South India based on site class at that location. Thus, this method can be viewed as a simplified method to evaluate the PGA values at any site in the study area.
Highlights
The Peninsular India is one of the oldest Archaean shield regions in the world, whose continental interiors are generally considered as seismically stable
In this study an attempt has been made to evaluate the seismic hazard based on peak horizontal acceleration (PHA) and spectral acceleration (SA) at rock level and peak ground acceleration (PGA) at ground level, based on different site classes, for South India based on probabilistic seismic hazard analysis
Using a newly developed MATLAB program, the hazard curves and Uniform hazard response spectrum (UHRS) for 2% and 10% probability exceedance in 50 years are calculated for 9500 grid points in the study area
Summary
The Peninsular India is one of the oldest Archaean shield regions in the world, whose continental interiors are generally. The PGA values at the ground surface for the entire study area were evaluated by considering four different site classes viz. The seismic hazard estimation for Peninsular India was previously attempted by Jaiswal and Sinha (2007) and their study area starts from 10◦ N. The study area selected is from 8◦ N and the earthquake data and details of seismic sources were collected for an area of about 300 km from the boundary of study area, as per Regulatory Guide 1.165 (1997) Apart from this there are major differences in the methodology adopted for the evaluation of seismic hazard. Site response effects were considered and the PGA values at ground surface for the entire study area were developed for four different site classes. A design response spectrum for Mumbai, based on site class D, has been developed based on Eurocode 8 (2005) and Indian standards code (BIS-1893, 2002)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
