A STUDY ON THE LIQUEFACTION POTENTIAL IN BANDA ACEH CITY AFTER THE 2004 SUMATERA EARTHQUAKE

Abstract

Liquefaction is caused by an earthquake in which the energy propagates into soil layers to trigger the excess pore water pressure escalation so that the soil mass liquefies. This condition causes a decrease in effective stress, ground settlement, and lateral spreading. This study aims to determine the liquefaction potential in Banda Aceh City, Indonesia, due to the Mw 9.2 great earthquake that occurred in 2004. The analysis was conducted on 16 boreholes incorporating Standard Penetration Test (SPT) that investigated the soil engineering properties and geological conditions of the study area. The peak ground acceleration (PGA) for each borehole location was obtained from the value determined by the Ministry of Public Works and Public Settlement of Indonesia. The analysis of liquefaction potential in Banda Aceh City adopted the semi-empirical of the Idriss Method with an input moment magnitude of 7, 8, and 9.2 Mw, respectively. The liquefaction potential was evaluated at 5 m, 10 m, and 15 m depths below the ground surface. The analysis resulted in 4zones of liquefaction potential levels, i.e., very high, high, low, and very low. High liquefaction potential zonesoccur in the Sub-districts of Baiturrahman, Kuta Alam, and Syiah Kuala. Meanwhile, low and very low liquefaction potential spread over the northeast, western, and southern parts of Banda Aceh.