Massive Earthquake Swarm in Antarctica Suggest Sleeping Volcano Awakening
There is some intriguing analysis that has just been released about a massive swarm of earthquakes that occurred in Antarctica in 2020.
A ‘swarm’ of 85,000 earthquakes in Antarctica that lasted about six months in 2020 was triggered by magma from an underwater volcano, a new study says.
The swarm occurred at Orca Seamount, a deep-sea volcano near King George Island in Antarctica, in the Bransfield Strait, which has been inactive for ‘a long time’.
Researchers have used seismometers and remote sensing techniques to determine how long the swarm lasted, and what caused it.
Swarm quakes mainly occur in volcanically active regions, so the movement of magma in the Earth’s crust is therefore suspected as the cause.
During the swarm, ground on neighbouring King George Island moved 4.3 inches (11cm) – suggesting a ‘finger’ of magma almost reached the surface, the scientists report in their new study.
The international team of researchers said the swarm was the most intense earthquake activity ever recorded in the region.
“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, told Live Science.
“Normally, these processes occur over geologic time scales,” as opposed to over the course of a few months, Cesca said. “So in a way, we are lucky to see this.”
The scientists used a variety of methods to track the swarm and its geophysical effects, including analyzing data from seismic stations in the region and satellites orbiting the Earth.
This data shed light on the potential causes of the huge swarm. According to the researchers, the movement of magma into the crust could explain the seismic activity.
The human contributions to “climate change” are dwarfed by volcanoes. The scale of the Antarctic volcanoes is not fully known, given the challenges of studying at that latitude. However, there is a strong possibility that a super-volcano could be under the massive ice sheets.
It’s not easy to see what’s going on below Antarctica’s ice sheet.
On average the ice is 2.6km thick. At its deepest, it is 4.7km down.
So NASA has taken all we know — from satellite and airborne observations through to every piece of applicable physics they could think of — and bundled it all together in a new simulation.
The end product of the calculations which reproduced the processes of friction, heat transport and liquid water behaviour revealed there has to be another source of energy down there.
A mantle plume fits the bill.
This mantle plume — some of which are known as supervolcanos — pumps out some 200 milliwatts of energy per square meter.
The background heating from beneath the Earth in non-geologically active areas is about 40 to 60 milliwatts.
The one under Antarctica appears to be roughly in the same league, at up to 150 milliwatts.
Any hotter and the simulations show the ice sheet melting too much to fit observations — except for one spot near the Ross Sea.
Intense flows of water have been seen here. The simulations needed up to 180 milliwatts of energy to produce similar results.
And those worried about climate extinction might like to reflect on the fact that the last time a super-volcano erupted, it almost wiped-out our species.
Professor Danisik and colleagues have studied Lake Toba in Sumatra, an apparently idyllic body of water that actually occupies the caldera of a supervolcano, measuring about 100km by 30km (62 by 19 miles) across.
This supervolcano is believed to have erupted roughly 74,000 years ago, and some researchers believe the eruption released six billion tons of sulphur dioxide into the atmosphere, leading global temperatures to plummet by 15C (59F) for three years afterwards.
While this scientific analysis of the impact of the eruption is disputed, scientists have suggested that the eruption caused a genetic bottleneck in human evolution.
The hypothesis is that between 50,000 and 100,000 years ago, human populations rapidly shrunk to just 3,000-10,000 individuals, a claim for which there is some genetic evidence.
Given the rock-hard science behind volcanic impact on the Earth’s climate, I find I cannot get worked-up about SUVs and cow farts.
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