Coseismic Surface Deformations of Global Large Earthquakes in 2014–2016 Detected by Alos-2 Insar

SAR interferograms were produced using ALOS-2 data to detect global coseismic deformations associated with large (magnitude ≥ 6) and shallow (depth ≤ 25 km) onshore earthquakes from August 2014 to December 2016. Substantially coherent interferograms were produced for all 30 targeted seismic events, even in tropical areas, where C-band Sentinel-1 interferometry is unreliable due to severe decorrelation. A high degree of coherence of the ALOS-2 InSAR also greatly helps to identify surface ruptures. In this study, surface ruptures were successfully identified in at least seven events. Moreover, left-looking observations of ALOS-2 enable the retrieval of three-dimensional coseismic deformations with high precision, including north-south components, although left-looking observations are conducted only in the onshore area of Japan. In the case of the 2016 central Tottori earthquake in Japan, a clear, four-quadrant, three-dimensional deformation pattern was retrieved, implying that almost pure sinistral slip occurred.