Seismo Lab Seminar

High-frequency seismic waveforms from large regional arrays have revolutionized our ability to explore earthquake rupture dynamics through back-projection (BP). In this talk, I present our advancements in enhancing the resolution and reducing uncertainties in BP imaging, providing new insights into fundamental questions regarding earthquake source processes. Leveraging the improved capability of slowness-enhanced BP combined with Rayleigh Mach wave identification, we systematically analyzed seismic records of significant shallow strike-slip earthquakes (Mw ≥ 6.7) from 2000 to 2020. Our analysis identified four oceanic supershear events, revealing that approximately 14% of large earthquakes within this timeframe exhibited supershear propagation, with comparable frequencies in oceanic and continental environments. In our recent work, a detailed investigation of the 2025 Mw7.7 Myanmar earthquake demonstrated an exceptional sustained supershear rupture extending about 450 km along the Sagaing Fault. Seismic and geodetic data, combined with satellite imagery of urban damage, confirmed its supershear nature and highlighted significant seismic hazards. These findings underscore the critical influence of fault geometry, fracture-to-elastic energy ratio, and bimaterial contrasts in facilitating supershear propagations.