Thousands of earthquakes occurring in rapid succession in less than a year under the Antarctic glacier, possibly connected with the tides of the sea.

The specialists studied seismic activity under the glacier David in East Antarctica, which takes about 700 km2. It serves as an outlet by which 4% of the glacial cover of this region goes into the ocean.

The speed of glaciers of the Antarctic on the basis of satellite data (image from NASA / JPL-Caltech / UCI).

The researchers analyzed data collected for the nine-month period in 2002-2003, in the course of Seismic experiment in the Transantarctic mountains" 42 seismometers. Allocated about 20 thousand seismic events that were strong and lasted longer than usual for glaciers shock.

"Amazing, the mere existence of such event, says glaciologist Lucas WEA (Lucas Zoet) from the University of Pennsylvania (USA). - This type of seismic activity was not observed earlier in the Antarctic outlet glaciers, so that at first, the main task was a simple classification".

Bewildered, the researchers found that the earthquake occurred at equal intervals of time - approximately 25 minutes. Experts suggest that the matter in motion loaded with fragments of ice flow on rough land of indigenous breeds, and regularity connected with the sea by the tide.

In particular, the tides affect the speed of the glacier, says Mr. the WEA. "At high water slowed a bit, and seismic events are posted in time, and at low tide they, on the contrary, become closer," says the researcher.

It remains unclear what other seismic changes may occur with sea level rise and when will happen the next big earthquake.

The study is published in the journal Nature Geoscience.

Based on the materials of Our Amazing Planet.