A Prior Study of Dempo Volcano Deformation using Global Positioning System (GPS) Surveys

Dempo Volcano is one of many active volcanoes in highly earthquake-prone Sumatran Island; this volcano is situated near Pagar Alam City and has been in alert level status since 2015. We have been conducted a series of Global Positioning System (GPS) Surveys since 2017 to study the deformation pattern associated with the activity of this volcano. GPS data were processed using GAMIT/GLOBK 10.6 software. Four observation stations were deployed to represent the activity on the body of Dempo Volcano (DMP1, DMP2, DMP3, TASE) and one reference station (ALVI) was set up far away from the influence Dempo Volcano (GAD). This study shows the vector direction inclined towards the north with the velocity rate at about10 mm/yr to 39.96 mm/yr with respect to ALVI reference station. This preliminary result shows a substantial amount of movement by the GAD. However, further research is needed with additional more stations and more data observation. Furthermore, a refine modeling of Sumatran Fault Zone (SFZ) movement has to be incorporated by selecting a more suitable reference station for the SFZ because the position of the ALVI station is relatively far from the SFZ.