Landslides in California occur mainly due to the dynamic tectonics

Tectonics

Tectonics is a field of study within geology concerned generally with the structures within the lithosphere of the Earth and particularly with the forces and movements that have operated in a region to create these structures.Tectonics is concerned with the orogenies and tectonic development of...

 along the San Andreas Fault Line. Southern California

Southern California

Southern California is a megaregion, or megapolitan area, in the southern area of the U.S. state of California. Large urban areas include Greater Los Angeles and Greater San Diego. The urban area stretches along the coast from Ventura through the Southland and Inland Empire to San Diego...

 proves to be a particularly active tectonic area, and also a common place for residential development.

California Geological Survey

In 1880 the California Geological Survey (CGS) took over surveying of the California landscape from the California State Mining Bureau. CGS Vision Statement reads:

CGS is regarded as the primary source of geological and seismological products and services for decision making by California’s government agencies, its businesses and the public.


Since the 1960s, the CGS has produced many maps to show landslide features that may affect potential slope-stability areas. The CGS provides Landslide-inventory maps, Landslide-potential maps, Landslide-risk maps, and Landslide-zone maps . These mappings are meant to show the different kinds of landslides including rock slides, earth flows

Earthflow

An earthflow is a downslope viscous flow of fine grained materials that have been saturated with water, and moves under the pull of gravity. They are an intermediate type of mass wasting that is between downhill creep and mudflow...

, debris slides, debris flows, and rock falls

Rockfall

Rockfall or rock-fall refers to quantities of rock falling freely from a cliff face. A rockfall is a fragment of rock detached by sliding, toppling, or falling, that falls along a vertical or sub-vertical cliff, proceeds down slope by bouncing and flying along ballistic trajectories or by rolling...

. The CGS provides a Seismic hazards

Seismic hazard

Seismic hazard refers to the study of expected earthquake ground motions at the earth's surface, and its likely effects on existing natural conditions and man-made structures for public safety considerations; the results of such studies are published as seismic hazard maps, which identify the...

 Zonation Program that provides map publications in the Landslide Inventory Map Series. This series is meant to provide maps of potentially high risk areas for development.

Mappings in California and Regulations

The State of California Department of Conservation

California Department of Conservation

The California Department of Conservation is a department within the government of California, belonging to the California Natural Resources Agency. With a team of scientists, engineers, environmental experts, and other layabouts, the Department of Conservation administers a variety of programs...

 maps the seismic hazard that trigger many of these landslides to protect public health and safety in accordance with the provisions of Public Resources Code, Section 2690 et seq. (Seismic Hazards Mapping Act). These mappings provide the state with a mapping of the probabilistic ground shaking through site-specific evaluations, and must exist before building occurs. The mappings provide three hazardous categories: amplified shaking hazard zones, 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...

 hazard zones in accordance with groundwater

Groundwater

Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock...

 conditions, and earthquake induced landslide hazards. These hazards are used to provide developers with potential hazardous areas, and provided by a registered civil engineer

Civil engineer

A civil engineer is a person who practices civil engineering; the application of planning, designing, constructing, maintaining, and operating infrastructures while protecting the public and environmental health, as well as improving existing infrastructures that have been neglected.Originally, a...

 or certified engineering geologist

List of historic Californian landslides

• La Conchita mudslide in La Conchita, California
  La Conchita, California
  La Conchita is a small unincorporated community in western Ventura County, California, on U.S. Route 101 just southeast of the Santa Barbara county line...
  
  , United States
  United States
  The United States of America is a federal constitutional republic comprising fifty states and a federal district...
  
   on January 10, 2005, killed 10 people and destroyed 18 homes
• Devil's Slide, an ongoing landslide in San Mateo County, California

External links

• http://www.consrv.ca.gov/CGS/codes/ccr/t14/Pages/3720.aspx Public Resources Code, Section 2690 et seq. (Seismic Hazards Mapping Act).