1,2,3,4,7,- 1Department of Earth, Planetary and Space Sciences, University of California Los Angeles, Los Angeles, CA, USA (xuliuw1997@g.ucla.edu)
- 2Observatoire de la Cˆote d’Azur, Universit ́e Cˆote d’Azur, CNRS,IRD, G ́eoazur, Rue Albert Einstein, France.
- 3National Key Laboratory of Microwave Imaging, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, China.
- 4School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, China.
- 5National Engineering Research Center for Remote Sensing Satellite Applications, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, China.
- 6School of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China.
- 7State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, China.
- 8School of Geoscience and Info-Physics, Central South University, Changsha, China
- 9Department of Earth Science, University of California, Santa Barbara, Santa Barbara, CA, USA.
Joint seismic and geodetic analyses reveal that the 2025 Mw 7.8 Mandalay, Myanmar earthquake ruptured ~510 km of the Sagaing Fault, including a sustained supershear rupture extending ~450 km along the southern branch and a shorter ~60 km subshear rupture to the north. The supershear nature of the southern rupture is independently confirmed by the observation of far-field Mach waves, comparisons between near-fault fault-parallel and fault-normal velocity components, and picks of ground-displacement onset times. This exceptionally long supershear rupture produced widespread building collapse, landslides, and soil liquefaction documented by satellite observations, highlighting the severe damage potential of such rupture modes in urban environments. We propose that the persistent supershear propagation was enabled by the fault’s linear geometry, prolonged interseismic quiescence, favorable energy ratio, and pronounced bimaterial contrasts across the fault interface. Together, these results emphasize the critical roles of fault structure, stress accumulation, and material contrasts in controlling rupture dynamics, and demonstrate that large-scale supershear propagation can occur on interplate continental strike-slip faults.
How to cite: Xu, L., Meng, L., Yunjun, Z., Yang, Y., Wang, Y., Hu, C., Weng, H., Xu, W., Su, E., and Ji, C.: Bimaterial Effect and Favorable Energy Ratio Enabled Supershear Rupture in the 2025 Mandalay Quake, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3206, https://doi.org/10.5194/egusphere-egu26-3206, 2026.
