Ground motion prediction equation for north India, applicable for different site classes

Abstract

The region of north India has been witnessing frequent earthquakes (EQs) and subsequent induced effects from time to time (1720 Delhi EQ, 1905 Kangra EQ, 1999 Chamoli EQ, 2005 Muzzafarbad EQ, etc.). The seismic hazard of the region is collectively due to Himalayan EQs as well as EQs from regional sources in Aravalli and Indo-Gangetic basin. Previously attempted seismic hazard studies in the region used ground motion prediction equation (GMPE) developed/found suitable for the Himalayas. Keeping in mind that the propagation path which seismic waves during an EQ take to reach north India, is through north India and not the Himalayas, existing GMPEs for the Himalayas have limited application for north India. Besides, unless details of site class (SC) of regional recording stations are available, ground motion records from these recording stations cannot be used to develop SC specific GMPE. This study utilizes source, propagation path, and site characteristics of north India, which were developed earlier by the current authors, to developed GMPE for north India using finite source model. Proposed GMPE is applicable for magnitude (Mw) range of 3.5–7.8, up to epicentral distance of 250 km and for NEHRP SCs A/B, C, D, and E separately. Proposed GMPE can be used to estimate seismic hazard as well as quantification of induced effects for the region and is first of its kind. Comparisons of regional records for each SCs with proposed GMPE show close matching.