This map describes the possible hazard from earthquake-induced
landslides for the city of Berkeley, CA. The hazard depicted by this map was
modeled for a scenario corresponding to an M=7.1 earthquake on the Hayward, CA
fault. This scenario magnitude is associated with complete rupture of the
northern and southern segments of the Hayward fault, an event that has an
estimated return period of about 500 years. The modeled hazard also corresponds
to completely saturated ground-water conditions resulting from an extreme storm
event or series of storm events. This combination of earthquake and
ground-water scenarios represents a particularly severe state of hazard for
earthquake-induced landslides. For dry ground-water conditions, overall hazard
will be less, while relative patterns of hazard are likely to change.
Purpose: The map is intended as a tool for regional planning. Any
site-specific planning or analysis should be undertaken with the assistance of a
qualified geotechnical engineer. This hazard map should not be used as a
substitute to the State of California Seismic Hazard Zones map for the same
area. (See California Department of Conservation, Division of Mines and
Geology, 1999). As previously noted for maps of this type by Wieczorek and
others (1985), this map should not be used as a basis to determine the absolute
risk from seismically triggered landslides at any locality, as the sole
justification for zoning or rezoning any parcel, for detailed design of any
lifeline, for site-specific hazard-reduction planning, or for setting or
modifying insurance rates.
