STUDY OF POSTSEISMIC DEFORMATION FOLLOWING THE 2018 PALU-DONGGALA EARTHQUAKE USING GPS DATA FROM APRIL – NOVEMBER 2019

• Main Author: Meidiana Syarif, Yasmin
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/53259
• Institution: Institut Teknologi Bandung

Indonesia is located in the high seismicity region due to plate boundaries and active fault intraplate. This condition makes this region vulnerable and has a high risk caused by earthquake disasters. One of the most devastating earthquake was the Palu-Donggala earthquake, occured on 28 September 2018 with magnitude M7.4. The Palu-Donggala earthquake ruptured along the Palu-Koro fault. This earthquake also caused secondary disasters such as tsunami, landslide, and liquefaction. All of these disasters had caused thousands of deaths and major material loss. These are the fundamental reasons of why mitigation is very important to minimize the damage impact of the earthquake disaster in the future. One of the mitigation efforts conducted after the Palu-Donggala earthquake is to monitor the Palu-Koro fault using Global Positioning System (GPS) data. These GPS stations, which located in Palu and the surrounding region, are process using Precise Point Positioning (PPP) method to obtain the relative displacement rate. GPS processing result show a significant displacement relative rate, indicating that the tectonic activity of Palu-Koro fault after the 28 September 2018 earthquake, identify as postseismic deformation, impacted the Palu area. Postseismic deformation modelling using log+log+exp function shows the postseismic deformation mechanism in Palu area with the short-term and long-term decay time. This study found that the decay time of afterslips are 6±2 days and 60±20 days and decay time of viscoelastic relaxation is 600±200 days.