Response of Geologic Units to The Ground Parameters of Tarutung Earthquake 2022 Mw 5.8: A Preliminary Study

Abstract

On 1st October 2022, a moderate crustal earthquake with Mw 5.8 occurred in the northen part of Tarutung region and was strongly felt by the local peoples and followed by massive damages. The occurrence of the Tarutung earthquake was firstly assumed in the southern part of the Renun fault then updated to the pull-apart system of Toru fault. Here, we concern about the ground paramaters that generated a massive shaking and connect with the recent geologic units beneath the Tarutung region. The peak ground acceleration (PGA) and peak ground velocity (PGV) clearly show an amplification case may arise in the basin formation that consists of Alluvium Formation whereas the attenuation to the west and east part with Martimbang and Sipoholon Caldera Formation. The PGV was ranging at 0 – 10 cm/s and the PGA was ranging at 0% – 16% gal which are suitable with the intensity range at 3 – 6 MMI. The PGV, PGA and intensity relationship show a possibility of the building damage percentage is up to 80% and 50% of the surrounding area may potentially experience a complete damage. The pseudo-spectral acceleration (PSV) at 0.3s, 1.0s, and 3.0s also show a potential damage that can be found at low-moderate building structure with 8% - 16% gal. The ground parameters show an empirical relationship that can be used to assess the possible of geologic units in the Tarutung region. Furthermore, our result benefits can be applied to support the mitigation program and environmental planning in Tarutung region in the near future.