M 7.1 - South Sandwich Islands region | WHAT REALLY HAPPENED X-Frame-Options: DENY X-Frame-Options: SAMEORIGIN

M 7.1 - South Sandwich Islands region

The August 22, 2021 M 7.1 earthquake in the South Sandwich Islands occurred as the result of normal faulting at approximately 14 km depth in the Scotia subduction zone. The focal mechanism solution indicates slip occurred on either a shallowly dipping fault striking north-northeast and dipping to the southeast, or on a steeply dipping fault striking to the south-southwest and dipping to the northwest. At the location of this earthquake, the South America plate subducts westward beneath the Scotia plate and South Sandwich microplate. The South America plate subducts at a rate of ~77 mm/yr relative to the South Sandwich microplate. The depth and location of this event indicate that it occurred as a result of slab bending within the upper part of the South America plate.

While commonly plotted as points on maps, earthquakes of this size are more appropriately described as slip over a larger fault area. Events of the size of the August 22, 2021 earthquake are typically about 50 km x 20 km in size (length x width).

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