Hi All. It looks like GPS could be the answer to earthquake prediction. While it is still too early to tell it does appear to be heading in that direction. Take Care…Don in creepy town

Dr. Yehuda Bock, a faculty member at the UCSD Scripps Institution of Oceanography and researcher at Cal-(IT)², says you may feel that you can never step on the same California twice.

Bock explains, "Over the last decade, we've been installing GPS tracking stations throughout southern California. These stations track the satellites continuously, and every 24 hours we recalculate the position of the sites relative to all other sites. By monitoring their positions over time, we can determine if the crust is moving in response to seismic activity. The ground is moving all the time because the plates are moving with respect to each other. But by monitoring over time, we can see how the movement relates to earthquake physics. Assessing position to study crustal deformation is our main goal."

The Hector Mine earthquake, which occurred October 16, 1999 and had a magnitude 7.1, helped Bock's group focus their activities. "We were able to observe and develop the technology to get a fix with one single measurement," says Bock. "If you can observe five satellites out of the seven or eight visible at any one time, you can instantaneously determine your position within a centimeter or two."

During the earthquake, Bock's group was able to 'see' the wave as it propagated through the crust because of the change it caused in the positions of the stations. The sample rate was only once every 30 seconds but, with more than 25 sites active in Los Angeles, they could see the L.A. basin literally resonating up, down, and sideways for several minutes after the quake.

• Yehuda Bock