Re-liquefaction hazard evaluation in flow-slide affected area of Jono Oge, Central Sulawesi, Indonesia

Abstract

The 2018 Palu-Donggala Earthquake with a moment magnitude (Mw) 7,5 caused a major damage in Central Sulawesi. This earthquake occurred as a result of strike-slip faulting north-south trending Palu-Koro Fault. This paper aims to determine the liquefaction potential in Jono Oge after the 2018 Palu-Donggala Earthquake. The liquefaction potential was evaluated from geological condition in the study area and 7 boreholes incorporating Standard Penetration Test (SPT). These data were carried out to evaluate liquefaction potential in Jono Oge using the simplified procedure SPT-based by Idriss-Boulanger method and liquefaction potential index (LPI) to assess liquefaction potential. The safety factor against liquefaction was used to calculate the probability of liquefaction that had been updated by Juang et al. This analysis expressed the potentially liquefied soil layers in varying depths. In flow-slide affected area, the liquefaction potential index was at high to very high level and very low level at the irrigation area. From the analysis, the re-liquefaction in Jono Oge could potentially occur in the future with the peak ground acceleration is at least 0.33g on a firm rock. The probability of re-liquefaction in the low safety factor layer varied between 59.18 – 99.84%.