Wednesday, September 26, the San Francisco Chronicle's website, SFGATE, published This article
Some summary information is below the orange magma chamber, but the entire article is definitely worth a read.
A huge earthquake that struck beneath the Indian Ocean in April triggered an extraordinary burst of large quakes around the world that alerted scientists to new seismic hazards everywhere.
At least four seismic faults deep underground off the island of Sumatra ruptured within 100 seconds to create a single giant quake with a combined magnitude of 8.7.This event was followed by "scores" of quakes worldwide, with at least 16 had magnitudes of over 5.5 and one in Baja California had a magnitude of 7.0.
Thorne Lay and Han Yue of UC Santa Cruz and Keith Koper of the University of Utah analyzed the April quake's unusually complicated fault ruptures. The resulting quake, they said, apparently broke through the upper part of a huge tectonic slab of the Earth's crust called the Indo-Australian Plate that butts against the Indian subcontinent.The completion of the plate fracture will take millions of years and involve many more megaquakes, but if they are correct, those who noted any of that April quake activity actually indirectly witnessed the start of new plate formation.
As a result, Lay said, the plate is apparently continuing to fragment into two separate tectonic plates and ultimately will create a new plate boundary