Why Are Shaking Hazard Maps Important?
	Based on ABAG "On Shaky Ground" Reports

The San Francisco Bay Area is in "earthquake country."

In some earthquakes, the surface of the ground can rupture along a fault -- or a landslide can be triggered -- or underground sand layers may flow (liquefy) -- or a tsunami ("tidal" wave) may be generated in water. But in ALL earthquakes, the ground shakes. In large magnitude earthquakes, more ground shakes, and it shakes longer, than in small magnitude earthquakes. Ground shaking causes damage tens of miles away from the fault source.

When the ground shakes, damage occurs to buildings, facilities and their contents. People can be injured or killed. People find that they may no longer be able to sleep in their homes, or even have access to their belongings. Businesses can't function and segments of the economy suffer. Hazardous materials are released which can be damaging to people and the environment.

Various options are available to avoid, reduce or otherwise mitigate these results. What YOU do to prepare for shaking can minimize or eliminate these effects.

Most earthquake damage is caused by the shaking of the ground itself. Yet, at the same time, many existing local and State government hazard reduction programs and regulations focus on other earthquake hazards. Our purposes in providing shaking hazard information are to expose ground shaking as a significant hazard, to show (using maps) the areas with the strongest expected shaking, and to suggest ways to mitigate shaking damage.

jbp 10/15/03