| Abstract Submission No. | ABS-3.1-0209 |
| Title of Abstract | Seismic hazard evaluation in Northeast India |
| Authors | G. Surve, Rabin Das*, Abhilash K. S |
| Organisation | North-East Geophysical Research Laboratory, IIG, Shillong -793005 |
| Address | North- East Geophysical Research Laboratory, IIG Shillong, Meghalaya, India Pincode: 793005 E-mail: ganpat_surve@yahoo.co.in |
| Country | India |
| Presentation | Poster |
| Abstract | The North East (NE) India region is one of the six seismically active regions in the world that lies in the zone V of the seismic zoning map of India. The rapid development of the region in the recent past has made it highly vulnerable to seismic risk. The present study provides an updated probabilistic seismic hazard analysis (PSHA) of the NE India region spanning over 22° - 29° N and 89° - 98° E. It employs a comprehensive and updated earthquake catalog for 260 years from 1762 to 2024. Three different seismic source models, linear, areal and smoothed gridded seismicity models were used to compute seismic hazard of the study area. Based on the seismotectonics of the region the study area was spatially divided into six seismogenic source zones. Suitable region specific ground motion prediction equations (GMPEs) and GMPEs developed for similar tectonic regions worldwide were used in the hazard analysis. To account for epistemic uncertainties due to the varied inputs used for the seismic hazard analysis the logic tree method is adopted assigning equal weightage to all the three source models. The ground motion parameters in the form of Peak Ground Acceleration (PGA) and Spectral acceleration (Sa) values at bedrock levels were estimated for the entire region by dividing the area into grids of size 0.1° * 0.1°, for probability exceedance (PE) of 2% and 10% in 50 years corresponding to return period of 2475 and 475 years. The results indicate high level of seismic hazard in the range between 0.4 and 0.55g for 10% PE in 50 years for the Indo-Burma ranges, Mishmi Block and some parts of the Eastern Himalaya. The results of the study may provide basis for the seismic microzonation of the area, earthquake engineering purposes and input to seismic risk assessment. |
| Keywords | Peak Ground Acceleration, Spectral Acceleration, Seismic hazard, Microzonation |