The earthquake measured 7.9 on the moment magnitude scale and was centered off Tolitoli Regency in Central Sulawesi, or 25 km from the Tonggolobibi village.

[4] The North Sulawesi Subduction Zone joins the Palu-Koro Fault at its westernmost tip.

The earthquake took place along a relay zone between the North Sulawesi Trench and Palu-Koro Fault.

The mainshock resulted in a large coulomb stress transfer component around the Palu-Koro Fault.

Stress transfer later brought the Palu-Koro Fault closer to rupture and eventually failed, causing the 2018 earthquake.

The tsunami penetrated 200 m (660 ft) up riverbeds and carried five boats, including two 500-ton motorboats 250 meters onshore.