Seismic waves from a Chile earthquake in 2010 triggered icequakes, tremors which rupture ice sheets, in Antarctica, reports a US study.
It was known previously that large earthquakes trigger seismic activity in remote parts of the Earth’s crust, but these results indicate that ice sheets are also sensitive to such events.
Seismic events aren’t rare occurrences on Antarctica, where sections of the frozen desert can experience hundreds of micro-earthquakes an hour due to ice deformation.
But in March of 2010, the ice sheets in Antarctica vibrated a bit more than usual because of something more than 4,800 kilometres away, a 8.8-magnitude Chilean earthquake.
A new Georgia Institute of Technology study published in the journal Nature Geoscience is the first to indicate that Antarctica’s frozen ground is sensitive to seismic waves from distant earthquakes.
To study the quake’s impact on Antarctica, the Georgia Tech team looked at seismic data from 42 stations in the six hours before and after the quake.
Zhigang Peng, an associate professor in the School of Earth and Atmospheric Sciences who led the study, says some of the icequakes were quick bursts and over in less than one second.
Others were long duration, tremor-like signals up to 10 seconds. They occurred in various parts of the continent, including seismic stations along the coast and near the South Pole.
Peng says the source locations of the icequakes are difficult to determine because there isn’t an extensive seismic network coverage in Antarctica.
“But at least some of the icequakes themselves create surface waves, so they are probably formed very close to the ice surface,” he says.
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