Crustal Deformation of the 2018-2019 Mount Agung, Bali, Indonesia, Eruption from Continuous GPS Data

Abstract:

After 53 years of inactivity, the Mount Agung in Bali, Indonesia, started to erupt on November 2017. The Indonesian Geological Agency reported that another eruption occurred on 29 December 2018 20:09 UTC. During the event, satellite image showed that the volcanic ash moves to the southeast region of the volcano with a volcanic ash rise reaching 5500 m above sea level. This study utilise continuous GPS (Global Positioning System) data located surrounding the volcano to investigate the pressure source during the volcanic activity from 1 December 2018 to 16 March 2019. We managed to estimate the location of pressure sources in the northwestern part of the volcano. For GPS data between 1-16 December 2018, we found that inflation of pressure source is estimated prior the eruption on 29 December 2018, which followed by a deflation for period between 17-31 December 2018. This study revealed a sequence of inflation-deflation of pressure source activity which correspond with over-pressurized hydrothermal fluids in the northwestern part of the volcano for a period between 1 December 2018 to 16 March 2019.