Hypocenters Relocation Using Double Difference Method Around Mount Agung, Bali

Abstract

Summary After a long sleep for 54 years, now we are surprised by the presence of seismic activities of Mount Agung that has recorded since September 2017. We can’t prevent the eruption, however we can observe magma movement in the body of volcanos. Hypocenters distribution is an important information that can be used to reveal the magma movement in the body of volcano. For a more accurate hypocenter, we did relocation of earthquake hypocenter that has occured in Mount Agung area, periode September–November 2017 (Catalog data from BMKG). We used Double Difference method that compute in HypoDD program. We success relocated 331 from 415 events that occured since September-November 2017 in Mount Agung area. The hypocenter distribution looks more accurate and earthquakes are located under Mount Agung with range depths 3–42 km. The dominant hypocenter distribution lies to the southwest of Mount Agung, ie toward the middle between Mount Agung and Mount Batur. Magma is going move toward the surface or in brittle zones of Mount Agung. The small eruption has occured in Mount Agung, so we expected a higher probabilty for a large eruption can be occure following these small eruptions.