Liquefaction potential in the governor's office of West Sulawesi after the 2021 Mamuju-Majene earthquake

Abstract

The Governor's Office of West Sulawesi Province is close to an active fault, which triggers its vulnerability to seismic activity. The Mamuju Majene Earthquake destroyed the Governor's office building with a magnitude of Mw 6.2 in 2021. The geological conditions at the site are alluvial deposit formations. In addition to the geotechnical conditions, it has the characteristics of sandy soil with fine to medium gradations. Liquefaction causes a loss of soil strength and an increased pore water pressure caused by vibrations on the earth's surface in the form of seismic waves. It causes a decrease in effective stress, ground settlement, and lateral spreading. This study aims to determine the potential for liquefaction in The Governor's Office of West Sulawesi using a simplified procedure method with a Standard Penetration Test (SPT). The Peak Ground Acceleration (PGA) value is determined using the RSA Human Settlements. The Liquefaction Potential Index (LPI) produces five zones of liquefaction potential levels. The analysis showed that The Governor's Office of West Sulawesi experienced liquefaction at a depth of 12-18 meters with a moderate to very high level.