DEFORMATION ANALYSIS OF EARTHQUAKES OCCURRING IN TARUTUNG FROM SEPTEMBER 1 TO OCTOBER 31, 2022 WITH DINSAR MULTITEMPORAL METHOD

Tarutung is an earthquake-prone area due to the geotectonic and geological conditions of Tarutung, which is traversed by the Renun segment and the active Toru fault, and is dominated by volcanic rocks, with podzolic-type soils that are very sensitive to erosion. The Tarutung earthquake that occurred on Saturday, October 1, 2022, at 02:28:41 WIB with a magnitude of 6.0 Mw, has caused a lot of damage and casualties in a number of North Tapanuli sub-districts. In this study, the multitemporal DInSAR (Differential Interferometry Synthetic Aperture Radar) method was used to observe the deformation caused by the Tarutung earthquake in the pre- seismic, co-seismic, and post-seismic phases. This method utilizes Sentinel 1A imagery, which can identify surface deformation with a high degree of accuracy, in cm-mm size The results showed the maximum deformation in the form of uplift based on LOS (Line of Sight) of 2 309 cm for pre-seismic in Pahae Julu sub-district, 5 105 cm for co-seismic in Pahne Julu sub-district, and 1.320 cm for post-seismic in Siborong-Borong sub-district. As for the minimum deformation in the form of subsidence based on LOS (Line of Sight) of 2.825 cm for pre-seismic in Adiankoting sub-district, 0.820 cm for co-seismic in Pagaran sub-district, and -2.101 cm for post-seismic in Siatas Barita sub-district. Thus, it can be seen that the maximum deformation in the form of uplift increased significantly in the co-seismic phase, while the minimum deformation in the form of subsidence decreased significantly in the post-seismic phase.