Hi All. It seems that the Sunda fault/trench may not be the only bad boy in the area of the M>9.3 quake last December. Take Care…Don in creepy town

McCloskey, working with Suleyman Nalbant and Sandy Steacy, found a dramatic increase in stress in the Sumatra fault, which cuts through the island of Sumatra and runs east of the subduction zone that ruptured last year. The Sumatra fault is a "strike-slip" fault in which two plates slide against each other horizontally.

Before the India-Burma subduction fault gave way, it was pushing on the Sumatra fault, "clamping it shut" says geophysicist Rob McCaffrey of Rensselaer Polytechnic Institute in Troy, New York. "When it's clamped it's hard to make it slide. Now there's an increased probability of it slipping."

McCloskey's team found that in places the stress along the Sumatra fault had increased by 9 bars. In 1999, the magnitude 7.4 Izmit earthquake in Turkey increased stress in a nearby plate boundary by just 2 bars, and triggered an earthquake of magnitude 7.1 three months later. McCloskey warns that a magnitude 7.5 earthquake could occur along the Sumatra fault.

While it would not cause a tsunami because the fault line is not beneath the ocean, a magnitude 7.5 earthquake under Sumatra would be devastating. "This one will be closer to buildings, maybe in Medan," says geologist Roger Bilham of the University of Colorado at Boulder.

http://www.newscientist.com/article.ns?id=mg18524914.500

http://www.newscientist.com/channel/earth/tsunami/dn7203

http://www.geotimes.org/mar05/WebExtra032805.html