M 7.0 - 23 km WNW of Port-Olry, Vanuatu

Tectonic Summary

The January 8, 2023, M 7.0 earthquake near the island of Espiritu Santo in the Vanuatu island chain of the southwest Pacific Ocean occurred as a result of thrust faulting on or near the boundary between the Australia and Pacific plates. The preliminary location, depth and focal mechanism of the event indicate rupture occurred on a northeast-dipping thrust fault consistent with the location and orientation of the subduction zone interface at depth in this region. The earthquake is located about 60 km to the east of the New Hebrides Trench, the bathymetric expression of the plate boundary between the Australia and Pacific plates, where lithosphere of the Australia plate subducts into the mantle beneath the North Fiji Basin. At the location of this earthquake, the Australia plate moves east-northeast with respect to the Pacific plate at a velocity of approximately 84 mm/yr.

The Vanuatu region frequently experiences large earthquakes; 22 events of M 7 or larger have occurred within 150 km of the January 8, 2023 event over the preceding century. The largest was an M 7.7 earthquake in May 1965, 60 km to the east of the January 8, 2023, event. Large earthquakes occur frequently near this event, including a notable swarm of seismicity in 2016 north of the January 8, 2023 earthquake.