Surface Deformation Monitoring Induced by Volcanic Activity of Mount Agung, Indonesia, by PS-InSAR Using Sentinel-1 SAR from 2014-2021

Mount Agung is an active volcano located in Bali island, Indonesia, which had been dormant since 1963. However, Mount Agung began to show volcanic activity with severe earthquakes in August 2017. The intense seismicity peaked in early October 2017, and the volcano did not erupt until November 21, 2017. However, a violent explosive eruption with rapid lava-spewing occurred, forcing 140,000 people to evacuate between November 25 and 29, 2017. This study aims to monitor surface deformation induced by volcanic activity of Mount Agung by Persistent Interferometric Synthetic Aperture Radar (PS-InSAR) using Sentinel-1 SAR from 2014-2021. This study employed 250 Sentinel-1 SAR satellite images (from October 2014 to April 2021). These results show that displacement increased from May to November 2017 and then decreased for about a year and a half before increasing from May to July 2019. The seismic activity started again on May 28, 2019, and the volcano erupted on June 13, 2019. Before this period, PS-InSAR had detected a small sign of increasing displacements, especially in the northern part of Mount Agung. Furthermore, PS-InSAR provided the surface displacement results from the pre-eruption, co-eruption, and post-eruption periods. These results will be significant for understanding the active cycle of Mount Agung and for predicting future potential crisis periods.