Subsurface structure model using geomagnet data of Palu valley after the 2018 earthquake

Abstract

Abstract The earthquake of September 28, 2018, has caused changes in the structure of subsurface rocks in the Palu Valley of Central Sulawesi. Differences in rock structure occur due to deformation by seismic waves generated by the earthquake. Analysis of structural changes and strain of rock carrying surfaces is performed using the geomagnetic method. This study aims to map the fractures and local faults below the surface after the earthquake. Magnetic measurements are carried out using the Proton Precision Magnetometer with several measuring points of more than 856 stations. The measured magnetic data was corrected to obtain the total magnetic field intensity. Euler deconvolution is then performed to estimate depth and estimate subsurface, structure models. The results showed that the study area was identified by local fault and fractures below the surface, with depths ranging from 0 to 2000 meters. Local fractures and fractures formed are generally north-south trending following the Palu Koro fault.