Line-of-sight displacement from ALOS-2 interferometry: Mw 7.8 Gorkha Earthquake and Mw 7.3 aftershock

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.