Seismic Landslide Hazard for the City of Berkeley, California

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.

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.