Difference between revisions of "Landslides and Debris Flows in the California Central Coast Region"

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(Precipitation)
(Precipitation)
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===Precipitation===
 
===Precipitation===
  
Precipitation is the major influence on landslides.<ref name= "sr185">[https://www.conservation.ca.gov/cgs/Documents/Landslides/Caltrans/SR_185/CT001mon%20Report.pdf Department of Conservation Special Report on Landslides for the Coast Highway Management Plan]</ref> Rainfall intensity, duration, and frequency are important factors related to slope failure.
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Precipitation is the major influence on landslides.<ref name= "sr185">[https://www.conservation.ca.gov/cgs/Documents/Landslides/Caltrans/SR_185/CT001mon%20Report.pdf Department of Conservation Special Report on Landslides for the Coast Highway Management Plan]</ref> Rainfall intensity, duration, and frequency are important factors related to slope failure. Many deep-seated landslides occur after prolonged, intense rainfall and towards the end of the rainy season as soil becomes fully saturated, weakening the stability of a slope.<ref name= "usgs">[https://www.usgs.gov/natural-hazards/landslide-hazards/science/rainfall-and-landslides-northern-and-central-california?qt-science_center_objects=0#qt-science_center_objects USGS Rainfall and Landslides in Northern and Central California]
  
 
===Wildfire and Vegetation===
 
===Wildfire and Vegetation===

Revision as of 17:49, 6 April 2020

An environmental summary created by the ENVS 560/L Watershed Systems class at CSUMB.

Summary

Landslides are a characterized as the falling or movement of soil or rock down a slope and can manifest through mudflows, mudslides, debris flows, rock falls, rockslides, debris avalanches, debris slides, and slump-earth flows.[1] This movement occurs when the down-slope force exceeds the strength of the soil or other material holding the slope together.[2] Typically, landslides take time to initiate movement as the soil saturates and ultimately moves at a slow pace, but can cause significant damage to buildings and other infrastructure. [3] Debris flows, a type of landslide, occur suddenly with shorter and intense rainfall creating a slurry that moves at a rapid pace and often can result in loss of life making them more dangerous.[3]

In the United States, landslides are an extremely destructive hazard. Landslides in the country cause approximately $3.5 billion in damage, and kill between 25 and 50 people annually.[4] On a more local scale, landslides are one of the most costly geologic hazards in Monterey County, costing millions of dollars yearly in infrastructure.[5] Surrounding Monterey, many other regions are prone to landslides. Along the coast, between Point Lobos State Natural Reserve and Capoforo Creek, 1,500 landslides were mapped in 2001 which indicated slope-failure is common.[6] Additionally, Los Padres National Forest contains at least 250 active landslide sites and over half of the forest is highly susceptible to slope failures.[7] In Hollister, the hillslopes are susceptible to slope failure as well. Creep, slump, and other earthflows are common in the area.[8] In California's Central Coast Region, landslides and flows are common due to rainfall and steep slopes. Other causes are present in the region which facilitate landslide occurences.

Causes

Precipitation

Precipitation is the major influence on landslides.[9] Rainfall intensity, duration, and frequency are important factors related to slope failure. Many deep-seated landslides occur after prolonged, intense rainfall and towards the end of the rainy season as soil becomes fully saturated, weakening the stability of a slope.[10]
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