Assessing seismic hazard from a potential magnitude 8.0 earthquake along the Indo-Burmese wedge and its impact on Northeast India

The 2016 Mw 6.7 Manipur earthquake in Northeast India caused significant structural damage across the region. This study simulates a plausible Mw 8.0 earthquake to assess its potential impact, employing the Empirical Green's Function Method (EGFM) to estimate probable ground motions while incorporating path and site effects. Fault parameters for the simulated event were validated using recorded data from the Manipur earthquake, revealing a similar rupture directivity pattern in the Peak Ground Acceleration (PGA) distribution between the element earthquake (a smaller recorded event used for modeling) and the simulated earthquake. PGA values across Northeast India ranged from 3 gals to 103 gals for the Mw 6.7 event and from 11 gals to 342 gals for the simulated Mw 8.0 earthquake, with Shillong recording the highest PGA due to seismic wave interference, rupture directivity, and site amplification, despite being situated 214 km from the intermediate-depth source zone (typically between 55 km and 160 km depth). The source depth likely enabled direct wave propagation over long distances, emphasizing the need to analyze simulated earthquake waveforms across varying geological formations. A comprehensive understanding of ground response parameters, simulation methodologies, and the effects of geological and geomorphological features is crucial for refining earthquake preparedness strategies in Northeast India.