Characteristics of Palu-Koro Fault based on Derivative Analysis and Euler Deconvolution Model of Gravity Data

Indonesia is located at the confluence of three plates, namely the Eurasian, Indo-Australian, and Pacific plates which causes the formation of an active fault line. One of these active faults is the Palu-Koro fault, Sulawesi, with a shift rate of 30-44 mm/year. A geophysical method such as gravity determines the fault’s characteristics. Gravity data is processed by a derivative analysis process in the form of First Horizontal Derivative (FHD) and Second Vertical Derivative (SVD), which is carried out to represent the type of fault, and the Euler Deconvolution method is used to determine the location and depth of the fault anomaly source. The results show that the Palu-Koro fault has a high anomaly value in the west of 0.00557-0.01087 mGal in the north-south direction on the FHD map and an anomaly value of 0 in the north-south direction on the SVD map. The source of the anomaly can be seen more clearly in the results of the Euler Deconvolution modelling at a depth of 50-400 m from the topography of the study area. The Palu-Koro fault is proven to have many structures at shallow depths with very active movements that can trigger earthquakes.