Abstract The Sagaing Fault (SF) accommodates major plate motion in Myanmar, yet large earthquakes along it have rarely been captured by modern geodetic and seismic observations. The 2025 Sagaing earthquake generated an exceptionally long rupture (∼535 km), offering a rare opportunity to investigate rupture dynamics along continental transform fault. We integrate complementary high‐resolution imaging geodesy, teleseismic and strong‐motion waveforms, back‐projection, and finite‐fault inversion to investigate rupture extent, process, and slip evolution. Our results reveal a marked bilateral asymmetry in both rupture extent and speed: it propagated ∼85 km northward at sub‐shear speeds and ∼450 km southward predominantly at supershear speeds (∼6 km/s), punctuated by short sub‐shear segments. We propose that structural barrier and stress shadows limited the extent, whereas the SF's bimaterial interface and local stress‐drop heterogeneity jointly may potentially drive the asymmetric, intermittent supershear behavior. These findings provide new insight into mechanisms controlling complex rupture on continental strike‐slip faults.
Liu et al. (Sat,) studied this question.