Sumatra Quake Shook Earth's Total Surface

WASHINGTON - December's great Sumatra-Andaman earthquake - the most powerful in more than 40 years and the trigger of a devastating tsunami - shook the ground everywhere on Earth's surface. Weeks later the planet was still trembling.

The quake resulted from the longest fault rupture ever observed - 720 miles to 780 miles, which spread for 10 minutes, also a record. A typical earthquake's duration would be 30 seconds.

The December quake was the first of its size to be measured and studied by the new worldwide array of digital seismic instruments.

Those results are starting to come in, with a special section of a half-dozen research papers on the quake appearing in Friday's issue of the journal Science.