Liquefaction is one of the effects following an earthquake, it is the soil strength loss due to the vibration of an earthquake. The earthquake which struck with a 7.7 magnitude on September 28th 2018 in Donggala and Palu, Sulawesi caused a series of disastrous events including a tsunami and aftershock liquefaction in Balaroa and Petobo, causing many casualties. The liquefaction can be investigated and possibly predicted by identifying and interpreting the subsurface structures. This paper identifies the geological structures in the subsurface using the gravity method. The study was carried out by 3D inversion modelling at locations 119.6-120.2 BT and 0.6-1.2 LS based on gravity data. The gravity data was gained from Global Gravity Model plus (GGMplus). The study from satellite and the Bouguer anomaly in the Central Sulawesi shows that it has gravity of -50 to 130 mGal. The 3D inversion model of the subsurface shows low density contrast around the areas of Palu, Balaroa, and Petobo with values of -0.055 to -0.05 gram/cm3 where these low density depths have been identified from 0-125 meters below the surface and even deeper to the southern part of the study area. This low density contrast is in accordance with the geological conditions of the Palu which is dominated by porous sediment layers which are capable of storing fluids that are the main factor in causing the liquefaction.
|Journal||IOP Conference Series: Earth and Environmental Science|
|Publication status||Published - 28 Jul 2020|
|Event||3rd Life and Environmental Sciences Academics Forum, LEAF 2019 - Depok, Indonesia|
Duration: 11 Jul 2019 → …
- subsurface modelling