Landslide++Effect+(After)

=~EFFECT OF LANDSLIDES!~=

Landslide damage from the Northridge earthquake was only moderate because the area of greatest landslide activity is not yet heavily developed. However landslides did, as described below, block roads; damage and destroy homes; locally disrupt water mains, sewers, and power lines; and damage oil- and gas-production facilities. Landslides in the Santa Susana and western San Gabriel Mountains blocked many roads and thus hampered relief efforts and exacerbated the overall transportation problems caused by the earthquake. Landslides impeded traffic flow that was diverted onto secondary highways as a result of the collapsed interchange at I-5 and California State Highway 14. Rock falls and rock slides closed many of the alternate routes across the San Gabriel Mountains from the Lancaster/Palmdale and Santa Clarita Valley areas (plate 1) to Los Angeles, and it was several days before some of these routes were cleared of rock debris and made available to commuters. Dozens of homes in the central and eastern Santa Monica Mountains were moderately or severely damaged by reactivation of deep block slides. Although the landslide features are subtle and the damage patterns complex, making it difficult to distinguish shaking damage from ground-failure damage in this area, many clusters of damaged homes clearly relate to reactivation of old, deep block slides. Fill failures in some areas also damaged hundreds of homes and other buildings. Shallow, disrupted slides also seriously damaged many structures. One large home in Pacific Palisades was destroyed when the bluff on which it was built failed during the earthquake and caused half the house to be torn loose and cascade down the steep slope (see photograph on report cover). In the Santa Susana Mountains, rock falls damaged or destroyed several non-residential buildings, but no injuries were reported. In Tapo Canyon, north of Simi Valley in the Santa Susana Mountains, rock falls came closest to hitting residences; fortunately, only outbuildings were crushed beneath rock falls.

Considerable damage also was done to roads, pipelines, and well machinery within oil fields in the Santa Susana Mountains from rock falls, slumps, and block slides triggered by the earthquake. Many pump pads, pipelines, and roads were undermined by deep slumps or inundated by rock falls from above during the earthquake. In the Aliso Canyon oil field at the southeastern margin of the Santa Susana Mountains, large earth-moving trucks were engaged for several months just in removing rock debris from the oil-field roadways. One block slide in the Aliso Canyon oil field severed well pipe and damaged a well pump that was located at the head of the failure. Landslides in the Ramona oil field, described previously, also seriously damaged oil-field infrastructure. Pacoima Canyon, in the San Gabriel Mountains, experienced extreme landslide damage during the earthquake. Several large rock falls and rock slides from the precipitous slopes of the canyon dumped hundreds of thousands of cubic meters of landslide debris into the canyon, which blocked access to Pacoima Dam and damaged areas around the dam. About 50,000 m³ of landslide debris was trucked from the canyon following the earthquake. Rock falls damaged the spillway and the shotcrete covering the dam abutment. Continuing failure of material weakened by the earthquake seriously hampered repair efforts.

An unfortunate additional effect of the rock falls and rock slides in the Santa Susana Mountains was an outbreak of valley fever (coccidioidomycosis), which can only be contracted by inhaling airborne dust containing the fungal spores that cause the disease (Jibson and others, 1994b). The highly disruptedlandslides triggered by the earthquake generated dense dust clouds that blew downwind (southwestward) into Simi Valley where a tight cluster of more than 150 cases of valley fever were diagnosed in the seven weeks following the earthquake (Centers for Disease Control and Prevention, 1994). During all of 1993, all of Ventura County had reported only 52 cases. Three valley fever fatalities occurred, which accounts for about 5 percent of the total earthquake fatalities. 1181793457Soraya Yousefi

Effects:

The efects of a Landslide can be devesatating. Everything is burried under rubble, dirt, and mud. People die because they are trapped under alll that dirt. They can't breath and suffacate. In La Conchita one sad story is about a family who lives in the community. The father went out to go get Ice cream and came back to find his family dead.:(. After a landslide all the debrie and ruble has to be cleaned up with big construction cars. The landslides can crush a whole city like in La Conchita.


 * - [|BILLYBOBNORTON]** [[image:http://www.wikispaces.com/user/pic/BILLYBOBNORTON-sm.jpg width="16" height="16"]] Jun 6, 2007 9:24 am