Line‐of‐sight displacement from ALOS‐2 interferometry: <i>M_w</i> 7.8 Gorkha Earthquake and <i>M_w</i> 7.3 aftershock

Abstract

Abstract Interferometric synthetic aperture radar (InSAR) is a key tool for the analysis of displacement and stress changes caused by large crustal earthquakes, particularly in remote areas. A challenge for traditional InSAR has been its limited spatial and temporal coverage especially for very large events, whose dimensions exceed the typical swath width of 70–100 km. This problem is addressed by the ALOS‐2 satellite, whose PALSAR‐2 instrument operates in ScanSAR mode, enabling a repeat time of 2 weeks and a swath width of 350 km. Here we present InSAR line‐of‐sight displacement data from ALOS‐2/PALSAR‐2 observations covering the M w 7.8 Gorkha, Nepal earthquake and its M w 7.3 aftershock that were acquired within 1 week of each event. The data are made freely available and we encourage their use in models of the fault slip and associated stress changes. The M w 7.3 aftershock not only extended the rupture area of the main shock toward the east but also left a 20 km gap where the fault has little or no coseismic slip. We estimate this unslipped fault patch has the potential to generate a M w 6.9 event.