Strong Quake, Antarctica

A strong undersea earthquake struck the South Sandwich Islands early this morning.

Tuesday, 16 July 2013

A magnitude 7.3 earthquake struck 218 km south-south-east of Bristol Island in the South Sandwich Islands at 2:04 this morning, New Zealand time. The quake, which was 19 km deep according to the U.S. Geological Survey (USGS), was centred off the coast of Antarctica, south-east of the continent of South America. The epicentre was 2600 km south-south-east of Ushuaia, Argentina, 2200 km south-east of the Falkland Islands.

The Pacific Tsunami Warning Centre issued one bulletin for the Caribbean, reporting the quake as magnitude 7.2. It advised that a destructive widespread tsunami threat did not exist, based on historical data.

Geoscience Australia reported the quake as magnitude 7.2 at a depth of 73 km. It estimated that the quake would have caused damage within 120 km of the epicentre, and would have been felt up to 1500 km away.

The Joint Australian Tsunami Warning Centre issued one bulletin for the event, advising that there was no tsunami threat to the Australian mainland, islands or territories.

The USGS advises that the earthquake occurred about 100 km east of a complex triple junction between the South America, Antarctica and Sandwich tectonic plates. A magnitude 7.4 quake struck the boundary between the South America and Antarctica plates in 2006, and a magnitude 7.5 earthquake struck in 1973.

[ Compiled from data supplied by the U.S. Geological Survey, Pacific Tsunami Warning Centre, Geoscience Australia and the Joint Australian Tsunami Warning Centre. ]

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