ANALISIS POLA VARIASI REGANGAN PADA DEFORMASI DI SEKITAR KEPULAUAN MENTAWAI, SUMATERA BARAT, MENGGUNAKAN DATA GPS (GLOBAL POSITIONING SYSTEM) TAHUN 2010 - 2019

• Main Author: Ibrahim, Irfan
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/48723
• Institution: Institut Teknologi Bandung

The Mentawai Islands, located near the subduction zone, have the risk of an earthquake. In this zone, the Australian Plate moves closer to the Sunda Plate at any time causing energy accumulation. Energy accumulation, known as seismic moment, is centered on the contact zone between the two plates. This study aims to analyze the strain as a impact of deformation due to subduction zone activity around the Mentawai Islands. GPS (Global Positioning System) technology is considered a technology that is able to describe the phenomenon of deformation because of its high spatial or temporal accuracy. GPS time series data is the initial data used in this study, consisting of 16 Sumateran GPS Array (SuGAr) station points and 8 GPS CORS Badan Informasi Geospasial (BIG) station points in 2010-2019. The data is given some corrections including coseismic effect correction, outlier correction, and block motion correction. Then the velocity vector calculation process is done by modeling the time series data that has been corrected with a linear line equation. The results of this study indicate the SLBU point has the largest velocity vector with an average annual velocity of 87.5822 mm / year. While the smallest value comes from the PSKI station with an average annual velocity of 6,5250 mm / year. Based on the visualization of the velocity vector, it is found that the pattern of point movements generally leads northeast. Based on the velocity vector data, strain components consisting of extensions and compression are then calculated. The largest extension value obtained from SLBU-SMGY-KTET is 2,324852 microstrain. Meanwhile, the smallest value obtained from the points that is farthest from the subduction zone is JMBI-LNNG-CMUK with a value of -0.001292 microstrain. The highest compression value is -1.4121 microstrain originating from S1PO-PPNJ-KTET. While the smallest value is -0.1144 microstrain TRTK-PPNJ-CSEL.