Honshu Earthquake Causes Antarctic Ice Stream to Speed Up
18.03.2011 - Land & Geology, Ice & Snow, Antarctic
The earthquakes that struck Japan on March 11th caused the Whillans Ice Stream in West Antarctica to momentarily speed up, University of California, Santa Cruz scientists reported in the New Scientist. The ice stream, which drains ice from the West Antarctic Ice Sheet into the Ross Ice Shelf, has been monitored since 2007. The GPS data the scientists collected allowed the scientists to show that the ice stream witnesses two spurts a day in 30-minute slip events.
While the glacier normally advances one metre per day, slip events push it forward almost half a metre at a time. These rapid movements, the researchers say, result from the tides, and generate seismic waves that can be recorded by stations at the South Pole and in the Antarctic Dry Valleys.
When analysing GPS data from the ice stream, the scientists noticed that one slip event had happened earlier than expected. Further analysis revealed that the event happened exactly when surface seismic waves generated by the magnitude 9.0 earthquake in Japan would have hit Antarctica. The team now wants to further examine data from other major earthquakes to gain more insight into the possible effects of large earthquakes on glacier motion.
