Advancing earthquake hazard mitigation: Ground motion prediction for the Himalayan region

A Ground Motion Prediction Equation (GMPE) for the Himalayan region has been developed using 472 earthquake recordings from 108 earthquakes in the Himalayan region. The developed GMPE model incorporates parameters such as moment magnitude, hypocentral distance, site classification, and fault mechanism. The proposed GMPE follows the equation: log ( Y ) = c 1 + c 2 M w − c 3 ln ( X ) − log ( X + e c 4 M w ) + c 5 S + c 6 F + σ ( ε ) σ ( ε ) = τ 2 + ϕ 2 Where Y represents the Peak Ground Acceleration (PGA) or Spectral Acceleration ( S a ) in g, M w is moment magnitude, X is the hypocentral distance in km, and c 1 , c 2 , c 3 , c 4 , c 5 , and c 6 are the regression coefficients, S differentiates by 1 for the soil site and 0 otherwise. F accounts for fault type, where 1 indicates a reverse fault and 0 otherwise. σ ( ε ) is the standard error of the residuals, which is the standard deviation of the residuals and shows the uncertainty in the ground motion prediction. τ is event-to-event variability, and ϕ accounts for within-event variability. The value of σ ( ε ) varies from 0.36306 to 0.44714 for different spectral periods between 0.01 and 4.0 s. Weighted nonlinear regression analysis was employed to find the GMPE coefficient due to the scarcity of the observed data. Mixed-effect residual analysis was used to find τ and ϕ across all the periods. Evaluation of the developed GMPE through residual analysis indicated unbiased residuals, with minimal standard deviation in predicting PGA and S a at various periods (0.1 and 1.0 s) and 5 % damping. The developed GMPE was compared with different GMPEs developed for the Himalayan region and other parts of the world. The comparison revealed differences in predicted PGA and PSA values at lower distances, possibly influenced by variations in earthquake data and dataset sizes. However, at a distance of more than 50 km, the present GMPE is in good agreement with the other GMPEs. The developed GMPE is applicable for the magnitude range from 3.5 to 7.9, hypocentral distance up to 1000 km, rock sites ( V s 30 more than 700 m/s), soil sites ( V s 30 less than 700 m/s), and reverse and other types of faults. • A GMPE is developed from 472 records of 108 Himalayan earthquakes, offering improved site-specific seismic hazard estimates. • The GMPE uses site class (rock/soil) and fault type (reverse/other), improving reliability across diverse geological settings. • The GMPE aligns well with regional and global models beyond 50 km, confirming its suitability for Himalayan tectonic conditions. • Valid for M3.5–7.9 and distances to 1000 km, the GMPE aids seismic design, risk analysis, and mitigation in the active Himalayan zone.