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A comprehensive deterministic seismic hazard assessment (DSHA) of the north and central Himalayas (NCH) is attempted in the current study using recently developed strong-motion data-based region-specific ground motion prediction equations (GMPEs). Two source models, linear and point sources are used for hazard assessment. An updated seismotectonic map of the NCH is developed by identifying and merging the seismic sources from the Seismotectonic Atlas (SEISAT 2000) developed by the Geological Survey of India and recent literature, and a homogenized, declustered up-to-date earthquake catalogue with events since 250 BC. The NCH is divided into grids of size approximately 5 km × 5 km, and the bedrock level peak ground acceleration (PGA) at the center of each grid point is estimated using a region-specific GMPE considering both source models. The PGA values estimated at these points are exported to a GIS platform to develop a seismic hazard map of the region, separately for different sources, average and maximum of both the sources. It is observed from the current study that the PGA estimated is apparently greater than what is recommended in the codal provisions for seismic zonation and estimation of design horizontal acceleration for the NCH. Research highlights: SHA based on the state of the art DSHA technique has been carried out using various source models and recently developed region-specific GMPEs with an updated homogenized and declustered catalogue. Deterministic Seismic Hazard contour maps have been developed representing the bedrock level horizontal acceleration developed using linear and point sources. The newly developed hazard maps for the North and Central Himalayas shows higher PGA in the range of 0.4g to 0.7g towards the plate boundary region and a decreasing trend towards the peninsular shield region and the southern alluvial plains, except at the National Capital Region. The PGA estimated are comparatively higher than the design horizontal acceleration prescribed for these regions in BIS 1893. [ABSTRACT FROM AUTHOR]

The present study attempts to assess the seismic hazard parameters (a, b and M c) and their spatial variation in western Himalaya, central Himalaya and Indo-Gangetic plain areas (19–38 ∘ N and 72–91 ∘ E ). The earthquake catalogue is prepared from different available sources, within a region of 500 km surrounding the study area, in moment magnitude scale. The maximum likelihood estimation method is used for spatial variation of seismicity parameters. The study area is disaggregated into small grids of 0.5 ∘ × 0.5 ∘ , and the spatial variation of seismicity parameters is analysed for the complete catalogue period. A significant variation in seismicity parameters is observed while moving from west to east along the Himalayan belt within the study area. Due to significant variations in seismicity parameters, instead of assigning a lumped value of seismic hazard parameter to the entire region, distributed seismic hazard parameter is assigned by dividing the entire area into five zones, of similar level of seismicity. The estimated seismicity parameter a for these zones varies from 4.28 to 6.18, and for b, it varies from 0.80 to 1.03. Using these Gutenberg–Richter parameters a and b, the present study estimated the return periods and probability of different magnitudes of earthquake for each zone. [ABSTRACT FROM AUTHOR]