what is the landslide type of the la conchita? what is the landslide type of the la conchita?
Debris-flow source areas are often associated with steep gullies, and debris-flow deposits are usually indicated by the presence of debris fans at the mouths of gullies. Coarse particles such as sand grains have high frictional strength but low cohesive strength, whereas the opposite is true for clays, which are composed of fine particles. Let us know if you have suggestions to improve this article (requires login). The two formations are in fault contact along the active Red Mountain Fault, which extends across the slope face. A type of landslide in which the distribution of particle velocities resembles that of a viscous fluid is called a flow. The 2005 landslide was a shallower remobilization of the very same material into a rapid, highly fluid debris flow that buried 10 people. People were evacuated and the houses nearest the slide were completely destroyed. These schematics illustrate the major types of landslide movement. Study with Quizlet and memorize flashcards containing terms like A comprehensive term for any type of downslope movement of Earth materials is, What strategy has been suggested to stabilize the La Conchita, California, landslide?, In Yosemite National Park, strong bedrock influences the formation of what types of hillslopes? The bluff above La Conchita has produced a variety of landslides over an extended period of time. Since that time, other slides have occurred, covering at times cultivated land, roadways, and the community itself.[4]. In a rotational slide the axis of rotation is roughly parallel to the contours of the slope. Maps displaying where shallow landslides are most likely to occur are based on observation of previous landslide activity, topographic slope, and information on the bedrock material (seePreliminary soil-slip susceptibility maps, southwestern California-Open-File Report 2003-17). On January 10, 2005, a landslide struck the community of La Conchita in Ventura County, California, destroying or seriously damaging 36 houses and killing 10 people. Earthflow: Earthflows have a characteristic hourglass shape (fig. Landslide Preparedness | U.S. Geological Survey These reports and maps can be used as examples of what may occur during the upcoming 2015-2016 El Nio season if heavy precipitation occurs. Debris flow: A debris flow is a form of rapid mass movement in which a combination of loose soil, rock, organic matter, air, and water mobilize as a slurry that flows downslope (fig. The difference between slides and flows is gradational, with variations in fluid content, mobility, and type of movement, and composite slide movement and flow movement are common. There are five basic categories of flows that differ from one another in fundamental ways. The catastrophic movement of the 2005 landslide damaged or destroyed 36 houses and killed 10 people. . A translational slide typically takes place along structural features, such as a bedding plane or the interface between resistant bedrock and weaker overlying material. 8 What year did the landslide happen in Ventura CA? Our editors will review what youve submitted and determine whether to revise the article. These recent landslides spilled over U.S. Highway 101 in the Ventura County community that is located 25 miles south of Santa Barbara. A .gov website belongs to an official government organization in the United States. There were 10 confirmed fatalities. On March 10, a subsequent debris flow from a canyon to the northwest (see canyon on left part of figs. Know the Signs of a Deep-Seated Landslide 3H). Landslides are most abundant in areas underlain by marine shale . Get a Britannica Premium subscription and gain access to exclusive content. After the 1995 landslide, the town of La Conchita built a retaining wall at the foot of the hill. Alaska and Hawaii also experience all types of landslides. Heavy rains of January 1995 led to a March 4, 1995, landslide in the La Conchita Community of Ventura County (County), California. On January 10, 2005, a major landslide occurred in La Conchita. Reported landslides began in 1865. Shallow landslides can occur at any time during the winter, but are more likely happen when the ground is nearly saturated. This type of movement can subsequently cause the mass to fall or slide. landslide, also called landslip, the movement downslope of a mass of rock, debris, earth, or soil (soil being a mixture of earth and debris). The landslide killed 10 people, and destroyed or damaged dozens of houses. Adversely oriented discontinuity (bedding, schistosity, fault, unconformity, contact, and so forth), Contrast in permeability and/or stiffness of materials, Fluvial, wave, or glacial erosion of slope toe or lateral margins. These tools and the accessible reader may be obtained free from Adobe at Adobe Access. Publications. La Conchita lies on a narrow coastal strip about 250 m (800 ft) wide between the shoreline and a 180m (600ft) high bluff having a slope of about 35; above the top of the bluff is a gently rising terrace surface covered by avocado and citrus orchards (fig. From December 27, 2004, through January 10, 2005, the nearby city of Ventura received 378 millimeters (14.9inches) of rainfall, only slightly less than its mean annual total of 390 millimeters (15.4inches). A large section of the hillside slid down and buried several homes after receiving almost 30 inches of rain that winter. Figure 2. The project also helps to. Creep is indicated by curved tree trunks, bent fences or retaining walls, tilted poles or fences, and small soil ripples or ridges (fig. National Oceanic and Atmospheric Administration, 1995a, Climatological data annual summaryCalifornia 1995: National Climatic Data Center, v. 99, no. La Conchita, California - Wikipedia The two major types of slides are rotational slides and translational slides. The landslide area was approximately 350 m (1,150 ft) long and 80100 m (260330 ft) wide. 10.5: Landslide Types and Processes - Geosciences LibreTexts They move very quickly. The volume of material moved by the landslide was 2.8 cubic kilometers (0.67 mi 3) . 10 years after fatal mudslide, tiny La Conchita accepts the risks It does not store any personal data. 1 What type of slide is the La Conchita slide? February 1995 produced only about onethird of the normal rainfall, but a modest storm on March 23 produced 21 mm (0.81 in) of rain. Deformation continued as the rainy season began, and by December 1994, several open cracks on the hillside were channeling surface runoff into the subsurface. Various processes that weaken the shear strength of a slope may also activate landslides. What type of slide is the La Conchita slide? Major types of landslide movements. Even in the absence of additional significant rainfall this year (2005), the remainder of the 1995 landslide could still remobilize, most likely as a deep slumpearth flow similar to that in 1995. There are various direct methods of preventing landslides, such as modifying slope geometry, using chemical agents to reinforce slope material, installing structures such as piles and retaining walls, grouting rock joints and fissures, diverting debris pathways, and rerouting surface and underwater drainage. Debris-flow source areas are often associated with steep gullies, and debris-flow deposits are usually indicated by the presence of debris fans at the mouths of gullies. The movement near the head of the slide is largely downward, exposing a steep head scarp, and movement within the displaced mass takes place along internal slip planes, each tending to tilt backward. What type of slide is the La Conchita slide? - Heimduo In southern California, at least 25 cm (10 in) of rainfall during the winter is needed to nearly saturate the ground. 10 and 11). The landslide slumped as a coherent mass of material. In 1995, after an exceptionally wet winter, the landslide moved tens of meters (tens of yards) damaging nine houses. 10.5: Landslide Types and Processes is shared under a CC BY 4.0 license and was authored, remixed, and/or curated by LibreTexts. This cookie is set by GDPR Cookie Consent plugin. An idealized slump-earth flow showing commonly used nomenclature for labeling the parts of a landslide. Debris avalanche: This is a variety of very rapid to extremely rapid debris flow (fig. Fires that denude slopes of vegetation intensify the susceptibility of slopes to debris flows. The latter landslide killed 10 people, and destroyed or damaged dozens of houses. On January 14, 2005, at the invitation of the California Geological Survey, I visited La Conchita with James O'Tousa, contract geologist for Ventura County, and Pamela Irvine, Janis Hernandez, and Terry Jones, all from the California Geological Survey. Of primary interest to the general public and various Governmental entities is the current state of hazard at La Conchita. La Conchita ( / l kntit / ( listen); Spanish for "The Little Shell") is a small unincorporated community in western Ventura County, California, on U.S. Route 101 just southeast of the Santa Barbara county line. [2] It lies on a narrow strip of land about 250 meters (820 feet) wide between the shoreline and abutting a 180-meter (590ft) high bluff. The historic slides are part of the larger Rincon Mountain slide, which started many thousands of years ago and will continue generating slides in the future.. Several smaller landslides occurred between the summer of 1994 and March 1995, when the large slide occurred. 3G). Fires that denude slopes of vegetation intensify the susceptibility of slopes to debris flows. A few things, however, can be said. Rotational slip. Landslides are a type of "mass wasting" which denotes any down slope movement of soil and rock under the direct influence of gravity. The 2005 landslide involved few new materials and seems to have been a continuation of the original 1995 landslide. The 2005 landslide occurred at the culmination of an extremely wet 2week period (fig. A complete prediction of the process would include assessments of where, when, and how big. The bluff above La Conchita consists of poorly indurated marine sediment of the Monterey and Pico Formations. 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.