Two strong, undersea earthquakes have struck Vanuatu in the past day.
Monday 10th January 2011
A magnitude 6.6 earthquake struck 110 km west-north-west of Isangel on the island of Tanna, Vanuatu last night. The quake, which struck at 11:04 p.m. New Zealand Daylight Time, was centred 160 km south of the capital Port Vila at a depth of 17 km according to the U.S. Geological Survey.
Geoscience Australia reports the event as magnitude 7.0 at a depth of 35 km. It estimates that the quake would have caused damage within 100 km of the epicentre, and would have been felt up to 1200 km away.
The Pacific Tsunami Warning Centre issued a bulletin for this event at 11:13 p.m. NZDT. Reporting the quake as magnitude 6.9 at a depth of 61 km, it advised that no destructive widespread tsunami threat existed, based on historical data.
A magnitude 6.4 quake struck the same area at 6:22 this morning, New Zealand time. This earthquake was centred 125 km west-north-west of Isangel (170 km south of Port Vila) at a depth of 33 km according to the U.S. Geological Survey.
Geoscience Australia reports this event as magnitude 6.5 at a depth of 60 km. It estimates the quake would have caused damage within 60 km of the epicentre and would have been felt up to 750 km away.
The PTWC did not issue a bulletin for this event.
Both earthquakes have struck along the New Hebrides Trench located between Vanuatu (formerly known as the New Hebrides) and the Loyalty Islands. A shallow magnitude 7.3 earthquake struck the same area on December 26th, generating a small wave measured at 15 cm at Vanuatu. A series of about 20 aftershocks struck the region in following days, the largest of which was a magnitude 6.2 event on the afternoon of Boxing Day.
Earthquake activity surrounding Vanuatu had been easing in recent days, but has again picked up. Apart from the latest two strong quakes, seven earthquakes with magnitudes between 4.9 and 5.4 have been reported in the area by the U.S. Geological Survey since midnight.
[Compiled from data supplied by the U.S. Geological Survey and its contributing agencies, the U.S. National Oceanic & Atmospheric Administration’s Pacific Tsunami Warning Centre, and Geoscience Australia.]