The March 28, 2025 Earthquake in Myanmar: A Rupture Surface Model from Satellite Data on Earth’s Surface Displacements

A rupture surface model of the Mw 7.7 earthquake that occurred in Myanmar on March 28, 2025 is presented. The model is based on the solution to the stress-strain problem of a spherically layered planet caused by displacements on an embedded rectangular fault (F. Pollitz, USGS) and displacement data collected during the earthquake and within six following days, derived from Sentinel-1A satellite imagery (March 22, 2025 and April 3, 2025) using the offset tracking method. A regularization condition is applied, favoring slip directions close to right-lateral strike-slip. It is shown that the main displacements on the rupture occurred within the upper 5 km of the Earth’s crust and ranged from 5.0 to 6.7 m, while at greater depths the displacements were significantly smaller. An exception was a small segment of the fault located between 21.28° and 21.56° N, where the displacement in the upper layer was estimated at 4.5 m. Possible causes for the slight displacement deficit are explained in the study by the peculiarities of the aftershock process development. The constructed rupture surface model does not show significant variations in the slip magnitude along the rupture surface or the presence of local thrust or normal faulting components. GPS data collected since the early 2000s also indicate uniform elastic strain accumulation along the whole fault at an average rate of 20 mm/year, suggesting that the fault was locked over its entire length. The obtained results refine the rapid finite-fault model presented on the US Geological Survey website by accounting for the Earth’s sphericity and radial layering, as well as by applying the regularization condition for slip direction alignment with right-lateral strike-slip motion.