Bimaterial Effect and Favorable Energy Ratio Enable Supershear Rupture in the 2025 Myanmar Quake

Liuwei Xu, Lingsen Meng, Zhang Yunjun, Yidi Wang, Yanchen Yang, Changyang Hu, Huihui Weng, Wenbin Xu, Elizabeth Su, & Chen Ji

Submitted September 7, 2025, SCEC Contribution #14246, 2025 SCEC Annual Meeting Poster #TBD

At 12:51 p.m. local time on March 28, 2025, a magnitude 7.7 earthquake struck near Mandalay, Myanmar. To resolve the rupture process of this major strike-slip event, we applied finite fault inversion and Back-Projection to seismic and geodetic datasets. The results revealed a ~530 km rupture along the Sagaing Fault, with a sustained supershear rupture extending ~450 km southward. Far-field Mach waves and near-field ground motion further confirmed the supershear nature. This exceptionally long supershear rupture caused widespread building collapse and soil liquefaction, as observed in satellite imagery, highlighting the destructive potential of such events in urban areas. The sustained supershear propagation was facilitated by the fault’s linear geometry, prolonged interseismic quiescence, favorable energy ratio, and pronounced bimaterial contrasts across the fault interface. These findings underscore the critical roles of fault structure, stress accumulation, and material contrasts in enabling large-scale supershear rupture in complex continental settings.

Key Words
Myanmar earthquake, source imaging

Citation
Xu, L., Meng, L., Yunjun, Z., Wang, Y., Yang, Y., Hu, C., Weng, H., Xu, W., Su, E., & Ji, C. (2025, 09). Bimaterial Effect and Favorable Energy Ratio Enable Supershear Rupture in the 2025 Myanmar Quake. Poster Presentation at 2025 SCEC Annual Meeting.

Related Projects & Working Groups
Seismology