The swarm of 85,000 earthquakes was the strongest seismic outburst ever recorded in Antarctica.
© Joseph Sohm; Visions of America via Getty Images
The swarm, which began in August 2020 and subsided by November of that year, is the strongest earthquake activity ever recorded in the region. And the quakes were likely caused by a "finger" of hot magma poking into the crust, new research finds.
"There have been similar intrusions in other places on
Earth, but this is the first time we have observed it there," study co-author Simone Cesca, a seismologist at the GFZ German Research Centre for Geosciences in Potsdam, told Live Science. "Normally, these processes occur over geologic time scales," as opposed to over the course of a human life span, Cesca said. "So in a way, we are lucky to see this."
The swarm occurred around the Orca Seamount, an inactive
volcano that rises 2,950 feet (900 meters) from the seafloor in the Bransfield Strait, a narrow passage between the South Shetland Islands and the northwestern tip of Antarctica. In this region, the Phoenix
tectonic plate is diving beneath the continental Antarctic plate, creating a network of fault zones, stretching some portions of the crust and opening rifts in other places, according to a 2018 study in the journal
Polar Science.
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