Icequakes in Antarctica may have been triggered by an earthquake that took place on 27 Feb. 2010, according to a new study.
Chile was devastated by a magnitude 8.8 quake four years ago that created vast property damage around the nation. The geological event was centered near the village of Maule, Chile, 2,900 miles away from the frozen southern continent.
Georgia Institute of Technology researchers believe that quake may have broken ice sheets in Antarctica, setting the stage for icequakes to take place thousands of miles away from the epicenter.
"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," Zhigang Peng, associate professor at the Georgia Institute of Technology, said.
Icequakes are a shaking in an ice sheet, created by sudden movements occurring under the surface of the ice. These can be caused by a fracturing crevasse, similar to cracking in ice cubes, set into a warm drink. Other events that can trigger icequakes include sliding glaciers, icebergs breaking free from the ice sheets that formed them, and runoff of liquid water. Sounds of cracking, fracturing ice was jokingly called "The Bloop" when they were first recorded.
Antarctica has experienced massive earthquakes itself. The Tohoku tsunami caused two pieces of ice, each the size of Manhattan Island, to break off the southernmost continent. The Sulzberger ice shelf, the source of the icebergs, is located around 8,000 miles from the epicenter of the earthquake.
In 1868, a massive earthquake in Chile caused icebergs to break off from Antarctica, a series of events which was noted by sailors traveling through the region. Powerful seismic waves, called a surface wave, can radiate from the source of earthquakes, traveling near the ground at nearly the speed of sound.
Following the Maule event, 12 seismometers out of 42 currently in place in Antarctica registered icequakes. Although this was not definite proof of widespread icequakes following the seismic event, patterns detected in the movement of underground pressure waves suggested this fracturing was due to the Chilean quake. Most of the icequakes were centered on ice streams - rivers under the surface of the ice - and mountainous regions. Each of these terrains is rich with crevasses that could have been the source of the frozen events.
"We think the crevasses are being activated by the surface waves from this big earthquake coming through, and that's making the icequake," Jacob Walter, research scientist for the University of Texas, told reporters.
Investigation of the Chilean earthquake and its possible effect on triggering icequakes in Antarctica was profiled in the journal Nature Geoscience.