A deep underwater volcano near Antarctica has awakened, causing a swarm of 85,000 earthquakes to erupt.
The swarm, which began in August 2020 and subsided by November of that year, is the strongest earthquake activity ever recorded in the area. New research has found that the quakes were most likely caused by a “finger” of hot magma burrowing into the Earth’s crust.
“There have been similar intrusions elsewhere in Landbut this is the first time we’ve observed it there,” study co-author Simon Siska, a seismologist at the German GFZ Research Center for Earth Sciences in Potsdam, told Live Science.
“These processes typically occur over geological timescales,” Cesca said, as opposed to the course of a human lifespan. “So in a way, we’re lucky to see this.”
The swarm occurred around the seamount Orca, which is inactive volcano Which rises 2,950 feet (900 meters) from the sea floor in the Bransfield Strait, a narrow passage between the South Shetland Islands and the northwest tip of Antarctica.
In this area, Phoenix tectonic plate Diving beneath the Antarctic continental plate, creating a network of fault zones, stretching some parts of the Earth’s crust and opening faults elsewhere, according to a 2018 study in the journal polar sciences.
Scientists at research stations on King George Island, one of the South Shetland Islands, were the first to feel the rumble of small earthquakes. Word soon returned to Cesca and his colleagues around the world, some of whom were collaborating on separate projects with researchers on the island.
Siska said the team wanted to understand what was going on, but King George Island is far away, with only two seismic stations nearby. So the researchers used data from those seismic stations, as well as data from two Global Satellite Navigation System ground stations, to measure Earth’s displacement.
The study authors reported April 11 in the journal that they also looked at data from more distant seismic stations and from Earth-orbiting satellites that use radar to measure ground-level shift. Earth and Environment Communications.
The stations nearby are rather simple, but they were good for detecting the smallest earthquakes. Meanwhile, remote stations use more sophisticated equipment and can thus paint a more detailed picture of larger earthquakes.
By putting this data together, the team was able to build a picture of the underlying geology that caused this swarm of massive earthquakes, Siska said.
The two largest in the series were a 5.9-magnitude quake in October 2020 and a 6.0-magnitude quake in November. After the November earthquake, seismic activity waned. The study found that the earthquakes appeared to have moved the ground on King George Island by about 4.3 inches (11 cm).
Only 4 percent of this displacement can be directly explained by the earthquake; Scientists suspect that the movement of magma in the crust is largely responsible for the Earth’s dramatic transformation.
“What we think is that Fate 6 somehow created some fractures and lowered the pressure of the magma dam,” Siska said.
Siska added that if an underwater volcanic eruption occurred at the seamount, it likely would have occurred at that time.
But so far, there is no direct evidence of a volcanic eruption. To confirm that the massive shield volcano blew up its summit, scientists will have to send a mission into the strait to measure bathymetry, or the depth of the sea floor, and compare it to historical maps, he said.