Tuesday, November 13, 2012

Myanmar's Earthquake

About 90 million years ago (MYA), during the Cretaceous reign of Tyrannosaurus rex, the Indian Subcontinent split from the Antarctic Plate and began to drift to the NNE.  By the end of the Cretaceous, some 65 MYA, it started to collide with the massive Eurasian Plate, a process that has lifted the Himalayas and continues today.

On the morning of November 11, a magnitude 6.8 earthquake struck north-central Myanmar.  This quake, which was followed by a magnitude 5.8 aftershock, occurred along the Sagaing Fault, where the Indian Plate is both colliding with and slipping NNE along the edge of the Eurasian Plate.  Early reports indicate widespread structural damage and at least 12 deaths; tremors from the rupture were felt as far away as Bangkok, Thailand.

While most recent earthquakes have occurred along the subduction zones of the Pacific Rim and western Indonesia, compression quakes are common across southern Eurasia where the African, Arabian and Indian Plates continue to drift northward, colliding with their larger, relatively immobile neighbor.  Myanmar's quake was just the latest reminder that Earth's puzzle of tectonic plates remains in flux.