The frozen ice surface of Antarctica is receptive to tremors and seismic waves from distant earthquakes, researchers said after finding crucial leads from the 2010 earthquake in Chile that was responsible for the icequakes in the cold continent.
The study was conducted by the researchers at the Georgia Institute of Technology.
A magnitude 8.8 quake rocked Chile’s Maule on February 27, 2010, setting off a flurry of icequakes in Antarctica, each lasting from one to 10 seconds. The epicenter of the icequakes was 2,900 miles (4,700 km) north of Antarctica.
Icequakes are seismic tremblings occurs due to sudden movement within a ice sheet or glacier.
Lead author Zhigang Peng, a seismologist, said, “Regular icequakes probably occur all the time in Antarctica and other polar regions. What we found is that they occurred more during the seismic waves of the Maule event.”
Pengis is an associate professor in the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology in Atlanta.
According to the researcher, the study removed the longer-period signals as the seismic waves which were spread from the distant epicenter so as to find high-frequency signals from nearby source.
The researchers term these events as small icequakes. According to the findings, most of the icequakes were triggered during the long-period Rayleigh waves which were generated from the Chilean mainshock or immediately after they passed.
This was quite different from the micro-earthquakes that are triggered by Love and Rayleigh-type surface waves and are occurred in other tectonically active regions which are thousands of miles from large earthquakes.
Researchers say while the newly discovered icequakes only responded to volumetric deformation from distant events, micro-earthquakes were found reacting to both shearing and volumetric deformation. This was the only minute difference between the two.
The most evident indication of induced high-frequency signals were found at station HOWD near Ellsworth Mountains’ northwest corner.
According to the lead researcher, the exact source location of the icequakes was tough to find in the absence of widespread seismic network coverage in the cold continent.
This is not the first occasion when Antarctica has been touched by great earthquakes. Earlier in 2011, the Tohoku tsunami of Japan tore off two Manhattan-size icebergs from the Sulzberger Ice Shelf. Long back in 1868 too, the sailors had reported about a giant iceberg-calving event in Antarctica after the great earthquake in Chile in the same year.
The findings of the study were published in the journal Nature Geoscience.
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