A series of powerful earthquakes shook the South Pacific just before midnight local time Wednesday. The earthquakes included a shock that measured magnitude 7.3 and multiple pre- and after-shocks.
The largest 7.3 struck at 11:43 pm local time - 7:43 pm Tuesday night Tallahassee time - near the Vanuatu Islands. A pre-shock of magnitude 6.3 hit the same area about half an hour earlier. Several other 5.2 to 5.4 after-shocks have also occurred.
This very powerful earthquake occurred along a subduction zone where two of earth's tectonic plates move toward each other and collide forcing one plate to dip below the other. Such geologic set-ups are often the site of slip-thrust faults which can cause massive devastation and widespread tsunamis such as the Christmas 2004 Indian Ocean tsunami.
While moderate damage is likely on some of the nearby islands, the Pacific Tsunami Warning Center says that no tsunami is likely from this earthquake. Data buoy observations in the South Pacific around the area of the earthquakes support the forecast for no tsunami.
The largest quake in the string of earthquakes was centered about 55 miles below the surface. The epicenter - the point on the earth's surface directly above the center of the earthquake - was located about 45 miles southwest of Isangel on the island Vanuatu, or just over 1100 miles east-northeast of Brisbane, Australia. The heaviest damage is likely on Vanuatu and islands in the immediate vicinity of Vanuatu.
Damage reports have not yet been made available. This earthquake is the second strongest earthquake so far in 2008, the strongest being the 7.4 quake that rattled Indonesia in February. Closely following as the third most powerful is the 7.2 earthquake that hit sparsely populated southwest China.