The Palu-Koro Fault is a major left-lateral strike-slip fault running north-south through the island of Sulawesi in Indonesia, passing directly through the city of Palu and its narrow bay. It is one of the fastest-slipping faults in the region, accommodating the complex rotation of crustal blocks where several plates meet.
The fault slips at a rapid rate of several centimetres per year, reflecting the intense tectonic activity of central Indonesia. Its trace runs along a deep valley and continues offshore into Palu Bay, where the steep underwater slopes create additional hazards during earthquakes.
The Palu-Koro Fault produced the deadly 2018 Palu earthquake of magnitude 7.5, which triggered a devastating tsunami in the bay and widespread soil liquefaction that carried entire neighbourhoods away, killing several thousand people. The disaster highlighted how strike-slip faults near coastlines can generate unexpectedly destructive tsunamis and ground failure.