USGS Detects Massive 7.5-Magnitude Earthquake in South Atlantic, Says No Tsunami Danger to Islands

The United States Geological Survey (USGS) reported on Thursday it had detected an earthquake in the South Atlantic with a magnitude of 7.5 on the Richter scale. Despite the size of the quake, no tsunami warning has been issued.

According to USGS data, the earthquake occurred deep in the Earth's crust, at a depth of 63 kilometers. Its location was about 100 kilometers northeast of Montagu Island, part of the South Sandwich Islands, or 2,150 kilometers southeast of Stanley in the Falkland Islands. St. Helena is of about equal distance. The islands are a British dependency.

major #earthquake M7.5 strikes South Sandwich Islands Region 33 min ago. https://t.co/cxtmPI8MXG pic.twitter.com/9DDVaQQVbq

— EMSC (@LastQuake) August 12, 2021

​As the location was especially remote, with the closest spots of land being desolate volcanic islands, some of which are active, no one has reported having felt the earthquake on the European-Mediterranean Seismological Centre's website as of yet.

Another smaller earthquake of magnitude 5.9 was reported about 15 minutes later at a depth of 47.3 kilometers inside the Earth and about 50 kilometers north of the first quake. A few minutes after that, a third quake, also of magnitude 5.9, was also reported; however, it was much shallower, at just 18.9 kilometers deep.

A fourth quake was reported soon after the third, but several hundred kilometers to the south, near the Southern Thule Islands, which are also uninhabited. The quake was magnitude 5.7 in strength and occurred at a depth of 48 kilometers into the Earth. More than a dozen such aftershocks came in the hours after the initial quake, scattered along the length of the fault line east of the South Sandwich Islands and falling between the strengths of 4.6 and 5.8 magnitude.