Land deformation due to earthquake in Cianjur, West Java, Indonesia: A multisensor-multitemporal study

Abstract

Background The Java Island is located in a seismically active region, which makes it vulnerable to earthquakes. On 21 November 2022, an earthquake of magnitude 5.6 struck Java, with its epicentre located in Cianjur, West Java. The earthquake caused significant damage to the buildings and infrastructure in the region, and several injuries and fatalities. Methods In this study, we used multisensor and multitemporal data to investigate the land deformation. Multi-pairs of Sentinel-1 SAR and aerial orthomosaic photos are used. Sentinel-1 SAR data were acquired from the Copernicus Data Space Ecosystem and the SNAP software was used to do inSAR analysis, while aerial orthomosaic data were acquired using DJI Drone Mavic Pro. Results Our results show that the earthquake caused significant land deformation in the area, with surface displacements of up to 9.8 cm and 11 cm for land uplift and land subsidence, respectively. We also found that deformation was primarily concentrated in the south-eastern and north-western parts of the study area. We identified the possibility of an unmapped fault that could trigger earthquakes in the future. Conclusions Our findings highlight the usefulness of radar and remotely sensed optical data in studying the effects of earthquakes. This data can be used to effectively design future disaster response and recovery efforts.