Old fractures caused rare 8.6 magnitude earthquake
Friday, August 31, 2012 - 14:30
in Earth & Climate
On 11 April 2012, an 8.6 magnitude earthquake occurred 100 kilometers (62 miles) off the coast of Sumatra. This earthquake was unusual in that it originated within the plate rather than at a plate boundary. In fact, it is the largest such earthquake in observed human history. The quake originated under the Wharton Basin in the Indian Ocean, where hundreds of kilometers of rock were under crushing tension, causing the plate to deform at its base. But this deforming zone was also absorbing tension as two plates, the Indian and Australian plates, rotated toward each other.