Analyzing Strong Earthquakes in the Central Himalayan Region in Nepal

Abstract

This is a descriptive-analytical research design study that analyzes strong earthquakes (magnitude ≥5) that occurred in the Central Himalayan region over the past 210 years (1800–2010). Data from multiple international catalogs, including the National Earthquake Information Center (NEIC), United States Geological Survey (USGS), International Seismological Centre (ISC), and Global Centroid Moment Tensor (GCMT), were compiled and homogenized for analysis. A total of 225 significant earthquakes were examined for spatial, temporal, and depth distribution, b-value estimation, and seismotectonic interpretation. The results reveal that the majority of seismic events were shallow, concentrated mainly along the Main Central Thrust (MCT) and Main Boundary Thrust (MBT). The estimated b-value (0.89) indicated high stress accumulation and suggests the potential for future major earthquakes. Spatial and temporal analyses highlight distinct zones of seismic clustering and variable activity over time, with increasing seismicity in the last five decades due to improved detection networks. The findings underscore the dominance of thrust and strike-slip faulting mechanisms within the Himalayan compression zone, driven by the ongoing convergence of the Indian and Eurasian plates. This work contributes to understanding regional seismotectonics and seismic hazard potential across Nepal and adjoining regions.