In an interesting example of synchronicity, the current issue of Scientific American has an article on earthquake warning systems, including the one in Japan. Obviously this issue was in print before Japan's quake. The article is written by Richard Allen, professor of geophysics and director of the seismological laboratory at the University of California Berkeley, who is currently testing a prototype system.

Part of the article discusses efforts to develop such a warning system for California. The cost is said to be about $80 million. Currently, the sensors are planned to be clustered around the Bay Area and Los Angeles. It's pointed out, though, that the Japanese system is in a regular grid pattern across the whole country, which gives much more accurate warnings.

It also discusses the issue of one seismometer detection which would be good for quick local warnings to that of waiting for multiple seismometers to be triggered, which would give a more accurate measure of location and magnitude at the expense of warning time.

Only an abstract is currently available online, but I've linked to it anyway. Maybe after a month or two when the print issue is no longer current, the full article will be available online.

Brian

• Seconds Before the Big One