On predictability of slip, rupture geometry, and speed of the 2025 M7.8 Mandalay, Myanmar, earthquake.

Subsurface fault geometry and slip distribution of the 2025 M7.8 Mandalay earthquake could be anticipated from pre-event observations, with slip exceeding the slip deficit.

• Why it matters: Understanding fault behavior and rupture dynamics in vulnerable regions is crucial for seismic hazard assessment and preparedness. This work addresses the challenge of predicting rupture characteristics using observational data before a major quake occurs.
• What they did: The study combines remote sensing and numerical modeling, analyzing along-strike deformation variations to reveal a helix-shaped fault geometry and generating 3D dynamic rupture models constrained by static slip data, discriminated with space-geodetic, seismic, and video observations.
• The result: The preferred rupture scenario involves bilateral initiation transitioning to unilateral southward supershear propagation at depth, with shallow rupture remaining subshear, highlighting the influence of localized stress heterogeneity and low fracture energy on rupture dynamics.