Integrated gravity, GNSS, and seismic analysis for fault mapping in Sulawesi island: Insights into the Palu-Koro Fault

The Palu-Koro Fault is one of the most active left-lateral strike-slip faults in Indonesia. This study integrates gravity data (GGMPlus), GNSS measurements, and seismic analysis to better understand the fault structure and tectonic behavior. The results show that the high First Horizontal Derivative (FHD) value along the fault corresponds to a sharp density gradient related to high tectonic activities. The secondary fault branches and lineaments can also be identified from Tilt Derivative (TDR), emphasizing the fault system's complexity. GNSS data from the INA-CORS network reveals patterns with notable extensional dilatation rates exceeding 100 nanostrain/year in pull-apart basins and compressional zones displaying significant uplift potential. Shear strain measurements highlight regions with deformation rates exceeding 250 nanostrain/year, particularly in the central Palu-Koro Fault segment. Seismicity clustering analysis indicates shallow to intermediate-depth earthquakes along the fault, majority at depths 20–30 km, reflecting lateral tectonic forces align with strike-slip Palu-Koro Fault activities. The integration of gravity, GNSS, and seismicity results critical insights into the fault's heterogeneity, deformation processes, and potential for large seismic events, contributing to enhanced hazard risk assessment and mitigation strategies in this geologically dynamic region.