Deformation Monitoring of Sipora Island Using Geodetic Global Positioning System Data

Abstract Sipora Island, in the Mentawai Islands, is an earthquake-prone area because there is a subduction zone, namely the collision between the Eurasian Plate and the Indo-Australian Plate. The continuous impact caused Sipora Island to store a considerable amount of energy that could reach more than 8.9 Mw, which may be released at any time. Therefore, monitoring the deformation of Sipora Island in the Mentawai Islands is necessary. Deformation can be monitored using a geodetic Global Positioning System (GPS). GPS makes observations at the SuGAr station on Sipora Island. Observations were made for 365 days, or one year of research, to be precise, in 2019. The observation uses five SuGAr stations and 16 IGS stations spread across the globe as a binder. In 2019, the deformation velocity vector on Sipora Island in the Mentawai Islands pointed northeast, in the same direction as the India-Australia Plate Shift. This shows that there is still a process of energy building up or inter-seismic processes. Meanwhile, vertically, the direction of the deformation shows that Sipora Island is experiencing subsidence.