Dynamic Triggering and Effects of Crust Heterogeneities on Propagating Waves due to the 2025 Mw 7.7 Myanmar Earthquake

We investigate the heterogeneity of the Indian subcontinent using seismic recordings from the Mw 7.7 Myanmar earthquake that occurred on 28 March 2025. This event was recorded by broadband stations across India. These variations in waveforms at different stations highlight the influence of radiation pattern, crustal structure, wave-propagation paths, and local site conditions. Sedimentary basins, characterized by relatively soft sediments, are known to amplify seismic energy and modify ground motion characteristics, often resulting in enhanced shaking. Understanding these effects is essential for assessing seismic hazard.

We use time-series data from approximately 88 seismic broadband stations provided by the National Centre for Seismology (NCS), India. We apply frequency spectrum analysis, horizontal-to-vertical spectral ratio (HVSR) analysis, and surface wave dispersion analysis. The frequency spectrum helps identify frequency bands where seismic energy is amplified while HVSR analysis is used to estimate the site’s fundamental resonance frequency and the corresponding amplification factor. Surface wave dispersion analysis provides shear-wave velocity information, which is crucial for characterizing near-surface geological conditions.

Together, these analyses help us to understand the influence of local geological conditions at the receiver sites and contributes to a better analysis of regional seismic wave propagation and site-specific ground motion characteristics across the Indian subcontinent.