JIM BERKLAND, GEOLOGIST: The month of October, March, and April are the three most devastating earthquakes in terms of damage in the San Francisco Bay Area in history. And we are having on the 19th of this month not only the full moon, but within an hour the closest approach of the moon to the earth until the year 2016. The next day is the equinoctial tides. So you're bringing together three of the maximum tide raising forces. We know about the ocean tides. But there is also an Earth tide. And there is a tide in the ground water....