Hi John. I doubt that Petra or I can explain it to you so that you would be willing to accept even a remote possibility that it can and does occur. I know Ross Stein, Kate Hutton and Sue Hough are at a loss as to why it occurs and they have been studying it for many a moon now. However something is occurring that isn’t truly understood. The cause of earthquakes isn’t fully understood let alone why one can trigger another 1000s of miles away. Take Care…Don in creepy town

Sue Hough:

“Theoretically, there are at least two sorts of remotely triggered earthquakes, said Hough.”

"One is where you're shoving real estate around," she said.

“That's when a quake changes stresses inside its local piece of crust and therefore applies new stresses to an adjacent pieces of the Earth's crust, causing shifting and quakes nearby. The effects can be on the order of hundreds of miles.”

"Such long-range triggering phenomena have been documented for the 1992 Landers (California) earthquake, the 2001 Denali (Alaska) earthquake and others," said seismologist Thorne Lay of the University of California at Santa Cruz and the Incorporated Research Institutions for Seismology (IRIS).”

“The second mechanism for remotely triggered quakes is less certain. It's where the seismic energy sent out through the Earth by a monster quake jostles fault zones thousands of miles away, triggering slips and jolts.”

“But from Sumatra to California?”

"We are talking changes in activity two-thirds of the way around the world, distant from a large event six months after," said Lay. "(It's) very tough to validate any statistical correlation or physical mechanism operating over that distance and time scale."

“That doesn't mean it can't happen. It's just really hard to study.”

"These big earthquakes are profound events in the physics of the planet," Hough said. And if they are, in fact, causing distant faults to slip and it can be proven, it might reveal something about how earthquakes start, a vital missing clue in the quest for one of seismology's Holy Grails: earthquake prediction, she said.”

http://72.14.207.104/search?q=cache:VnOhvgWFYyIJ:dsc.discovery.com/news/briefs/20050711/califquake.html+remote+triggered+quakes+Landers+quake&hl=en&gl=us&ct=clnk&cd=5

• Remotely Triggered Quakes