Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. The term landslide describes a wide variety of processes that result in the downward and outward movement of slope-forming materials including rock, soil, artificial fill, or a combination of these. The volume of material moved by the landslide was 2.8 cubic kilometers (0.67 mi 3) . The 1995 landslide was a deep, coherent slumpearth flow that deformed plastically and moved slowly enough that people could get out of its way. The two formations are in fault contact along the active Red Mountain Fault, which extends across the slope face. 1) (34.4 degrees north, 119.5 degrees west). copyright Engineering Applications Figure 5. La Conchita, coastal area of southern California. The 2005 La Conchita landslide occurred at about 12:30 p.m. on January 10. 2) On figure 2, label the following: main scarp, head of slide, body of slide, toe of slide. Although many types of mass movements are included in the general term landslide, the more restrictive use of the term refers only to mass movements, where there is a distinct zone of weakness that separates the slide material from more stable underlying material. Debris flows are commonly caused by intense surface-water flow, due to heavy precipitation or rapid snowmelt, that erodes and mobilizes loose soil or rock on steep slopes. Some move slowly, while others can move rapidly with little notice. Legal. Falls are strongly influenced by gravity, mechanical weathering, and the presence of interstitial water. The La Conchita landslide then occurred on March 4. 8.4: Examples of Landslides - Geosciences LibreTexts The landslide scenarios sketched above potentially could impact any part of the La Conchita community. Morton, D.M., 1971, Seismically triggered landslides above San Fernando Valley: California Geology, v. 24, no. In 199495, about twice as much rain761 mm (29.96 in)fell during that period (National Oceanic and Atmospheric Administration, 1994b, 1995b). This indicates that the landslide material, although it flowed rapidly, was quite viscous and pushed structures in front of it rather than flowing around them or filling them with mud, as sometimes occurs with fully saturated debris and mud flows. Debris flows also commonly mobilize from other types of landslides that occur on steep slopes, are nearly saturated, and consist of a large proportion of silt- and sand-sized material. Secure .gov websites use HTTPS The bench at the top of the bluff is the head of a very large prehistoric landslide that affected the entire bluff. Reported landslides began in 1865. Answer-Based on the observation from the figure. Below are other science projects associated with this project. 2 and 3) damaged five additional houses in the northwestern part of La Conchita. Fast-moving, highly destructive debris flows triggered by intense rainfall are one of the most dangerous post-fire hazards. Updates? (Click on the image to view it as a large JPG file). Nearly all kinds of slope-failure processes have been or are currently active in the region. Publications. Mean seasonal rainfall at Ojai (20 km [12 mi] northeast of La Conchita) from October 1 through March 3 (the day before the landslide occurred) is 390 mm (15.37 in) (National Oceanic and Atmospheric Administration, 1994a, 1995a). Types of landslides Factors contribute to landslides Landslide in Utah. We also use third-party cookies that help us analyze and understand how you use this website. 13, 60 p. National Oceanic and Atmospheric Administration, 1994b, Climatological dataCalifornia, OctoberDecember 1994: National Climatic Data Center, v. 98, nos. Schuster. Photo taken March 8, 1995. The main mass that failed is on the southeastern margin of the larger ancient landslide that encompasses the entire front of the bluff (see fig. This apparently resulted from a highly hazardous situation involving a twophased landslide mechanism: (1) a saturated, highly fluid layer at depth on which the landslide mobilized that (2) carried a thick layer of drier, much more viscous material that effectively acted as a battering ram. An idealized slump-earth flow showing commonly used nomenclature for labeling the parts of a landslide. Although there are multiple types of causes of landslides, the three that cause most of the damaging landslides around the world are these: Original content from Kimberly Schulte (Columbia Basin College) and supplemented by Lumen Learning. The tragedy came 10 years after the hill collapsed in 1995 when nine homes were lost. These cookies track visitors across websites and collect information to provide customized ads. What year did the landslide happen in Ventura CA? 12). In 1995, the community experienced a major slide, which damaged and destroyed a significant portion of the community. Combination of two or more of the above types is known as a complex landslide. Saturated soil slumps down a curved surface. By clicking Accept All, you consent to the use of ALL the cookies. The dominant mode of movement is lateral extension accompanied by shear or tensile fractures. The lush, green vegetation visible in the southeastern (lower right in photograph) part of the 1995 deposit clearly indicates that drainage on and within the 1995 landslide deposit concentrated water in the part of the mass that failed in 2005. The landslide area was approximately 350 m (1,150 ft) long and 80100 m (260330 ft) wide. landslide, also called landslip, the movement downslope of a mass of rock, debris, earth, or soil (soil being a mixture of earth and debris). A. Weathering affects rocks from the outside in, forming an outer weathered zone or rind. The landslide occurred after a 15-day period of unprecedented records of rainfall in Southern California. Movement is caused by shear stress sufficient to produce permanent deformation, but too small to produce shear failure. Figure 4. { "10.01:_Why_It_Matters" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "10.02:_Classifying_Mass_Movements" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "10.03:_Erosion_and_Deposition_by_Gravity" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "10.04:_Driving_and_Resisting_Forces" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "10.05:_Landslide_Types_and_Processes" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "10.06:_Putting_It_Together" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()" }, { "00:_Front_Matter" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "01:_Science_of_Geology" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "02:_Rock_Forming_Minerals" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "03:_Rocks_and_the_Rock_Cycle" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "04:_Soil" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "05:_Plate_Tectonics" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "06:_Earth\'s_Interior" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "07:_Crustal_Deformation" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "08:_Earthquakes" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "09:_Volcanic_Activity" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "10:_Mass_Movement" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "11:_Hydrology" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "12:_Geological_Implications" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "zz:_Back_Matter" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()" }, [ "article:topic", "showtoc:no", "license:ccby", "licenseversion:40" ], https://geo.libretexts.org/@app/auth/3/login?returnto=https%3A%2F%2Fgeo.libretexts.org%2FBookshelves%2FGeology%2FFundamentals_of_Geology_(Schulte)%2F10%253A_Mass_Movement%2F10.05%253A_Landslide_Types_and_Processes, \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}}}\) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\), Original content from Kimberly Schulte (Columbia Basin College) and supplemented by, Creative Commons Attribution 4.0 International, Combination or two or more principal types of movement. Falls are abrupt movements of masses of geologic materials, such as rocks and boulders, that become detached from steep slopes or cliffs (fig. What was the type of landslide in recent 2005 La Conchita landslide? A block slide is a translational slide in which the moving mass consists of a single unit or a few closely related units that move downslope as a relatively coherent mass (fig. OF 05-1067, "La Conchita Ranch is sold for $2.5 million", "La Conchita Lawsuit Settled, But It's Not Over", "Settlement reached in La Conchita lawsuit", Assessing Landslide Hazard Over a 130-Year Period for La Conchita, California, https://en.wikipedia.org/w/index.php?title=La_Conchita_landslides&oldid=1134048066, 2005 natural disasters in the United States, Short description is different from Wikidata, Creative Commons Attribution-ShareAlike License 3.0, The 2005 La Conchita landslide is the setting of, This page was last edited on 16 January 2023, at 19:34. The 2005 landslide occurred at the end of a 15day period that produced record and nearrecord amounts of rainfall in many areas of southern California. From December 27, 2004 through January 10, 2005, Ventura received 378 mm (14.9 in) of rainfall, only slightly less than its mean annual total of 390 mm (15.4 in) (Wofford, 2005; National Oceanic and Atmospheric Administration, 1994a, 1995a). 3I). Figure 4 shows the rainfall distribution during the 19941995 rainy season. Saturated soil (soil filled with water) flows down a slope. Ultimately, the County prevailed against the plaintiffs on all claims. Wildland fires are inevitable in the western United States. The content on this page is copyrighted under a Creative Commons Attribution 4.0 International license. This also is consistent with the shallower, fluid mode of failure: shallow, rapid debris flows most commonly occur during periods of prolonged, intense rainfall with little or no lag time (Campbell, 1975; Keefer and others, 1987; Jibson, 1989). Based on the opinion that surface water infiltration from irrigation contributed to the landslide, seventy-one homeowners sued La Conchita Ranch Co. in Bateman v. La Conchita Ranch Co. A classification system based on these parameters is shown in table 1. The landslide, a complex slumpearth flow, destroyed or severely damaged nine houses. Earlier that morning, debris flows from canyons northwest of La Conchita reached Highway 101. People were evacuated and the houses nearest the slide were completely destroyed. Our editors will review what youve submitted and determine whether to revise the article. The bluff above La Conchita has a slope of approximately 35 degrees and consists of poorly cemented marine sediments. In both 1889 and 1909, the Southern Pacific rail line running along the coast was inundated. Future landslide activity could occur in the areas of the 1995 and 2005 landslides or in other areas and could damage or destroy any or all of the developed area. Alaska and Hawaii also experience all types of landslides. The bench at the top of the bluff is the head of a very large prehistoric landslide that affected the entire bluff. Even modest rain storms during normal, non-El Nio years can trigger post-wildfire debris flows. Similar combinations of large ancient landslides and smaller, recently active landslides also are present in areas southwest of the 1995 and 2005 landslides. Share sensitive information only on official, secure websites.. Environmental & Historic Preservation Guidance, Real Estate, Lending or Insurance Professionals, State, Local, Tribal or Territorial Governments, Preparedness Activities, Research & Webinars, Voluntary & Community-Based Organizations, Environmental Planning & Historic Preservation, National Business Emergency Operations Center, Ventura County Public Works - Transportation Department. What mitigation took place after the La Conchita slide? These maps em, 12201 Sunrise Valley Drive Reston, VA 20192, Preliminary soil-slip susceptibility maps, southwestern California, Southern California LandslidesAn Overview, Map of Historic and Prehistoric Landslides in Pacific Palisades, Landslides in Santa Monica Mountains and Vicinity, Preliminary Soil-Slip Susceptibility Maps for Southwestern California, Map of Fatal or More than $1 Million Damage in California from 1906 to 1984, Landslide Hazards at La Conchita, California, Southern CaliforniaWildfires and Debris Flows, National Assessment of Shoreline Change Part 4: Historical Coastal Cliff Retreat along the California Coast, Emergency assessment of post-fire debris-flow hazards for the 2013 Springs Fire, Ventura County, California, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center, National assessment of shoreline change, part 4: Historical coastal cliff retreat along the California coast, Southern California Wildfires and debris flows, Southern California landslides-an overview, Landslide hazards at La Conchita, California, Groundwater and Streamflow Information Program, Geology, Minerals, Energy, and Geophysics Science Center, Soil slips, debris flows, and rainstorms in the Santa Monica Mountains and vicinity, southern California. Debris flows include <50% fines. Wave energy is also typically higher during the winter, and particularly during El Nio events, thereby exacerbating the potential for coastal erosion. Mudflow.
Forgotten Early 2000s Kids Shows,
Steve Martin's Daughter Mary,
Cheesecake Mount Pleasant, Sc,
What Happened To Charlie Puth And Meghan Trainor,
Which Best Describes Richard Nixon's First Term As President,
Articles W
