Deformation Monitoring on Pagai Island Using Geodetic Data

Abstract The western area of Sumatra Island, especially Pagai Island, is an area that is prone to natural disasters. This is because the area is located at the confluence of the Indo-Australian and Eurasian plates. However, information regarding the magni- tude and direction of deformation has not yet been mapped. This study aimed to determine the estimated monthly changes in the deformation velocity and direction of deformation on Pagai Island in 2019. In this study, deformation measurements were carried out in the Pagai Island area using Geodetic GPS data from the SuGAr Network (Sumatran GPS Array) and IGS (International GNSS Service), which were processed using GAMIT/GLOBK 10.71 software for data 1 year from DoY (Day of Year) 001-365 by observing 4 SuGAr stations (SMGY, SLBU, BSAT, and PRKB) and 16 IGS stations. The results of this study indicate that the deformation velocity has a small value and is deformed by 24.8 mm at the SMGY station and 10 mm at the SLBU station due to shallow earthquake activity on February 2, 2019, in the Mentawai Islands. From this research, it is hoped that later, it can be information for disaster mitigation in the Pagai Island area.