Model Kecepatan Seismik 1-Dimensi dan Ground Motion Gempa Bumi Tarutung 2022 M5,8

Abstract

On 01st October 2022, a strong earthquake with a magnitude of Mw5.8 occurred in the northern region of Tarutung, causing significant damages and strongly felt by the local community. Initially, the Tarutung earthquake was assumed to occur in the southern part of the Renun fault, but later revised to the Toru pull-apart fault system. This study aims to relocate the earthquake hypocenter and determine a one- dimensional velocity model and ground motion in Tarutung. Peak Ground Acceleration (PGA) and Peak Ground Velocity (PGV) clearly indicated possible amplification effects occurring in the basin formations consisting of the Alluvium Formation, while damping occurs towards the west and east with the Martimbang Caldera and Sipoholon Formation. PGV ranged from 0 to 10 cm/s, and PGA ranges from 0% to 16% gals, corresponding to an intensity range of 3 to 6 MMI (Modified Mercalli Intensity). The relationship among PGV, PGA, and intensity suggested a possibility of building damage reaching 80%, with approximately 50% of the surrounding area being potentially affected by total destruction. Pseudo-spectral acceleration (PSA) at 0.3s, 1.0s, and 3.0s also indicated potential damage to low to medium-rise structures with accelerations ranging from 8 to 16 % gals. Furthermore, the findings of this study can be applied to support mitigation programs and environmental planning in the Tarutung area in the near future.