Seismic Hazards Mapping Act
Encyclopedia
The Seismic Hazard Mapping Act ("The Act") was enacted by the California
legislature in 1990 following the Loma Prieta earthquake
of 1989. The Act requires the California State Geologist to create maps delineating zones where data suggest amplified ground shaking, liquefaction
, or earthquake
-induced landsliding may occur ("seismic hazard zones").
The Act requires responsible agencies to approve only projects within seismic hazard zones following a site-specific investigation to determine if the hazard is present and inclusion of appropriate mitigation(s) if so. The Act also requires disclosure by real estate sellers and agents at the time of sale if a property is within one of the designated seismic hazard zones.
The Act called for the creation of an advisory board to the State Mining and Geology Board to advise on the Act's implementation. In a 2004 update to the seismic hazard zone mapping guidelines, this advisory body concluded the amplified ground motion hazard was already sufficiently addressed by the 2001 California Building Code. Consequently, zones for this hazard are not being mapped by the State Geologist.
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
legislature in 1990 following the Loma Prieta earthquake
Loma Prieta earthquake
The Loma Prieta earthquake, also known as the Quake of '89 and the World Series Earthquake, was a major earthquake that struck the San Francisco Bay Area of California on October 17, 1989, at 5:04 p.m. local time...
of 1989. The Act requires the California State Geologist to create maps delineating zones where data suggest amplified ground shaking, liquefaction
Liquefaction
Liquefaction may refer to:* Liquefaction, the general process of becoming liquid* Soil liquefaction, the process by which sediments become suspended* Liquefaction of gases in physics, chemistry, and thermal engineering* Liquefactive necrosis in pathology...
, or earthquake
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...
-induced landsliding may occur ("seismic hazard zones").
The Act requires responsible agencies to approve only projects within seismic hazard zones following a site-specific investigation to determine if the hazard is present and inclusion of appropriate mitigation(s) if so. The Act also requires disclosure by real estate sellers and agents at the time of sale if a property is within one of the designated seismic hazard zones.
The Act called for the creation of an advisory board to the State Mining and Geology Board to advise on the Act's implementation. In a 2004 update to the seismic hazard zone mapping guidelines, this advisory body concluded the amplified ground motion hazard was already sufficiently addressed by the 2001 California Building Code. Consequently, zones for this hazard are not being mapped by the State Geologist.