The unexpectedly large earthquake that hit Sumatra last month is forcing scientists to rethink common assumptions about earthquake physics, researchers say.
The magnitude 8.6 earthquake that struck in the Indian Oceanoff the western coast of Sumatra on April 11was one of the 10 largest earthquakesever recorded, and was felt as far away as Bangladesh and India. However, no quake-related fatalities were reported.
Seismologists have done preliminary studies on the earthquake and found that it had some unusual aspects, ones that could help them better understand earthquakes that happen away from the boundaries between tectonic plates and better appreciate how powerful those quakes could potentially be.
Odd earthquake
Unusually, this quake apparently occurred in the middle of an oceanic plate. All the other top 10 quakes happened at subduction zones, where one of the tectonic plates making up the Earth's surface is diving beneath another. [13 Crazy Earthquake Facts]
Also oddly, the Sumatra temblor was a strike-slip earthquake, where two parts of Earth's crust slide past each other. Strike-slip quakes are not typically so powerful ‹ the Sumatra event was "far and away the largest strike-slip earthquake ever recorded," said researcher Gregory Beroza, a seismologist at Stanford University. Its magnitude 8.2 aftershock was also among the largest recorded strike-slip earthquakes.