M 7.2 - 100 km WNW of Sola, Vanuatu

Tectonic Summary

The May 27, 2010, M 7.2 Vanuatu earthquake occurred as the result of shallow reverse faulting on or near the plate boundary between the Australia and Pacific plates in the Coral Sea region of the southwest Pacific. In the region of the earthquake, the Australia plate moves to the east-northeast relative to the Pacific plate at a velocity of about 91 mm/yr. The Australia plate thrusts under the Pacific plate at the New Hebrides Trench west of the May 27th earthquake and dips to the northeast, remaining seismically active to depths of about 350 km beneath the islands. The May 27th earthquake’s location, depth, and focal mechanism solutions are consistent with the earthquake resulting from reverse faulting associated with subduction along the Australia-Pacific plate boundary.

This earthquake occurred between 70 and 130 km to the north of a sequence of large subduction thrust earthquakes in October 2009. On October 7, 2009, two earthquakes of M 7.7 and M 7.8 occurred 15 minutes apart. After these events, a M 7.4 aftershock struck approximately 1 hour later, and two M 6.6 and M 6.8 aftershocks occurred on the following day. In general, the Vanuatu region experiences a very high level of earthquake activity, with almost 50 events of M 7 or larger recorded since 1973.

Hayes et al. (2016) Tectonic summaries of magnitude 7 and greater earthquakes from 2000 to 2015, USGS Open-File Report 2016-1192. (5.2 MB PDF)