The South Pacific Ocean has continued to shake and rattle with earthquakes near the island chain of Vanuatu. The United States Geological Survey has registered several earthquakes of varying magnitude in the past two days with the largest being a 7.1 magnitude that struck at 12:34 a.m. local time on Friday, February 3. These earthquakes have epicenters offshore, about 77 miles west of Port-Vila on the island of Efate in Vanuatu.
* The USGS website shows at least 18 earthquakes (including the 7.1 magnitude quake) in this location since February 1, with one quake measuring 6.0 in magnitude and the larger 7.1 quake. The other quakes in the region ranged in size between 4.7 and 5.7 in magnitude.
* Most of these quakes had moderately shallow depths of around 25 miles or less, but two quakes that struck prior to the 7.1 magnitude temblor were much deeper. Those two quakes struck Thursday morning about 22 hours before the larger quake and Thursday evening, about three hours prior to the larger quake. These quakes were just under 5 in magnitude and they struck farther east, one located 11 miles southeast of Porta-Vila and the other 57 miles northeast of Porta-Vila. These quakes had depths of 91 and 148 miles.
* The website Radio New Zealand International reported that the initial 7-magnitude quake was felt by a number of people living on Efate but that there were no reports of damages or injuries. This quake reportedly lasted a few seconds and awakened many people from sleep as it struck just after midnight.
* According to the CIA Factbook, Vanuatu is part of Oceana and is a group of islands located between Hawaii and Australia in the South Pacific Ocean.
* Vanuatu is made up of four main islands and 80 smaller islands. The islands are mountainous, volcanic islands of which 65 are inhabited.
* Vanuatu is located just east of what is known as the New Hebrides Trench, a 750-mile long and 45-mile wide trench. The New Hebrides Trench is the location where two tectonic plates meet -- the Australian plate and the Pacific plate. This earthquake occurred where a corner of the Australian plate subducts or dives underneath the Pacific plate.
* Vanuatu is part of the Pacific "Ring of Fire" that produces a large portion of the world's earthquakes every year. The ring of fire mainly follows the plate boundaries surrounding the large Pacific plate.
* Vanuatu experiences frequent earthquakes in the 6- and 7-magnitude ranges. According to the USGS, the largest within the last five years to strike near the Vanuatu islands occurred in 2009 when two large earthquakes struck on the same day -- October 7. On that date a 7.7 magnitude and a 7.4 magnitude earthquake struck near Vanuatu.
Tammy Lee Morris is certified as a Community Emergency Response Team (CERT) member and is a trained Skywarn Storm Spotter through the National Weather Service. She has received interpretive training regarding the New Madrid Seismic Zone through EarthScope -- a program of the National Science Foundation. She researches and writes about earthquakes, volcanoes, tornadoes, weather and other natural phenomena.
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