landslide (mudslide) at La Conchita, a coastal community about 112 km west of Los Angeles. The basin extends from the rim of the volcano to the foothills at an altitude of 2,850 m a.s.l. In 1995, A Large Landslide Occurred, Damaging About A Dozen Homes. LA CONCHITA, CA - DECEMBER 07: A man bicycles past bluffs burned in the Thomas Fire on December 7, 2017 in La Conchita, California. Figure 5: Essentially the same tragedy strikes La Concitas (Conchita) a decade after the first landslide. PART 4: LA CONCHITA CASE STUDY La Conchita is a small coastal community near Ventura, CA. Importantly, computer simulation with LS-RAPID software using input parameters obtained from physical experiments is employed to interpret the entire formation process of the abovementioned two landslide dams. La Conchita is a small Pacific coastal community that lies between Santa Barbara, CA and Ventura, CA. the January 10, 2005 La Conchita landslide. Mitigation measures were taken to reduce/prevent future. Mitigation of debris flow hazards can therefore be accomplished by reducing this interaction, that is by altering the behaviour of either debris flows or humans, or both. Note: the two ovals on the topographic map in Figure 5 show the location of the 1995 and 2005 mass wasting events. LA CONCHITA, CALIFORNIA 2005 RICHARD HANSON, KRISTEN DALRYMPLE, BRACKON TAYLOR LOCATION La Conchita Study Resources View desktop site. From December 27, 2004, through January 10, 2005, the nearby city of Ventura received 378 millimeters (14.9 inches) of rainfall, only slightly less than its mean annual total of 390 millimeters (15.4 inches). John Morgan, 56 . Morphological comparison of the Carlson landslide with lobate martian landslides suggests a role for water in the martian landslides. Owing to such complex factors as deep valleys, steep mountains, varied topography and complex geological structures, it is extremely hard for people to obtain exact leveling data about this area. Notice the dirt road that traverses the hillside above the town. In an earlier tragedy at La Conchita, Ventura County was not held liable after 600,000 tons of mud and rock slid down the hill into the ocean-side town in 1995, destroying nine homes. This was not the first destructive landslide to damage this community, nor is it likely to be the last. As a prevention to future debris flow, have been constructed walls of containment (gabions) along the principal channel of the river La Ciénaga, nevertheless in every rainy season the gabions are saturated and frequently destroyed, which shows the intense activity of the remove gravitational processes. This is Part I of a two-part causation analysis of the January 10, 2005 La Conchita, California, USA landslide. Moreover, critical rainfall thresholds can vary from place to place in relation to the climatic and geomorphological conditions of the area. The January 10, 2005 La Conchita Landslide Philip J. Shaller 1 , Parmeshwar L. Shrestha 1 , Macan Doroudian 1 , Douglas L. Hamilton 1 , and David W. Sykora 2 1 Exponent, 320 Goddard Way Suite 200, Irvine, CA 92618 2 Exponent, 9 Strathmore Road, Natick, MA 01760 The fronts of the more fluid surges slithered and splashed along about like a rapidly advancing tongue of water. 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. Details. This abundance of landslide dams is probably caused by the geotectonic background of this area, which is located at the western end of the “Fossa Magna” major tectonic line. 27. During Typhoon Morakot, the flood level was beyond the design limit of many river embankments in southern Taiwan. The total duration of rainfall usually has a greater effect on these landslides than does the number of short periods of very intensive precipitation. In this study, the large-scale landslide that occurred in Hongye Village, Taitung County in Eastern Taiwan, on, Large landslides or debris flows caused by heavy rainfall or earthquakes often block rivers in mountainous areas and form landslide dams. and geology is, Access scientific knowledge from anywhere. A state of emergency was declared in 2005 after 10 people were killed by a reactivated landslide in La Conchita, California [Jibson, 2005]. Landslide Mapping and Geomorphologic Change Based on a Sky-View Factor and Local Relief Model: A Cas... Three Large Historical Landslide Dams and Outburst Disasters in the North Fossa Magna Area, Central... Sequence of instability processes triggered by heavy rainfall in the Northern Italy, Gravitational Processes in the Eastern Flank of the Nevado de Toluca México. The landslide is … & © 2003-2021 Chegg Inc. All rights reserved. Some days after an intense rainfall period, large landslides involving the bedrock can still take place. the countermeasures to prevent geological calamities are proposed. Ten people died in the 2005 La Conchita landslide: Tony Alvis, 53 . No breaker-like motion was evident, although the top of the front tended to shoot ahead of the base. This paper describes the development and application of a twodimensional finite difference model (FLO-2D) model to simulate the debris flow over a fixed substrate. Nanping City is located in the north of Fujian province, All right reserved. Physical characteristics for a debris flow: 30. Typically occur within proximity to mountain ranges. The immediate cause of flowage was rapid melting of deep winter snow. From December 27, 2004 through January 10, 2005, the nearby city of Ventura received 378 millimeters (14.9 inches) of rainfall, only slightly less than its mean annual total of 390 millimeters (15.4 inches). Field studies, eyewitness accounts, and movie films provide the following information. Debris or earth material that moves downslope due to the combination of an outside force and gravity. landslides. First bedrock landslides can occur, reaching a considerable area density, with volumes from a few hundred up to about one to two million cubic meters. This paper describes the geology and geomorphology of the event, which killed 10 persons and damaged or destroyed 36 residences. Laogan Ravine is a tributary of Xiaojiang River which is a branch of the Yangtse River in North-eastern Yunnan province, China. In continuous precipitation, in the third phase, basins of more than 2000 km2 in area reach their first critical stage. Rainfall (mm) Rainfall (mm) 10/1/2004 10/1/1994 10/11/2004 10/11/1994 10/21/1994 10/21/2004 10/31/1994 10/31/2004 1994-95 11/10/1994 2004-2005 11/10/2004 11/20119941 11/20/2004 11/30/1994 12/10/1994 11/30/2004 12/20/1994 Figure 6: Rainfall totals for Ojai (1994-1995) and Ventura (2004-2005). The community lies on a narrow strip of land about 250 meters (820 feet) wide between the shoreline and abutting a 180-meter 1590 Ft) high bluff. Over 30,000 m3 of wet debris was mobilized in the event, which formed two distinct lobes of debris. This can provide important information about avalanche speeds. The three-phase sequence has been identified in three severe events that are analysed in this paper: Valtellina (Lombardy) in 1987, Tanaro Valley (Piedmont) in 1994 and Aosta Valley in 2000; but this sequence has also been observed during other events that occurred in northern Italy: in Piedmont in 1968, 1977, 1978, 1993 and 2000; in Lombardy in 1983 and 1992; in the Aosta Valley in 1993. fourth-highest elevation in Mexico (4,662 m a.s.l.) This debris flow control project was completed in 1994 with total investment of 1.372 million Yuan. Debris flow hazards are the outcome of natural processes of erosion and sediment motion interacting with human systems. in Fujian Province. On July 26, 1985 a large debris flow overturned a bus and killed 12 passengers, silted up the open railway tunnel and highway bed with total 410m long. Earlier mudflows have occurred here, and others will undoubtedly take place in the future. PART 4: LA CONCHITA CASE STUDY La Conchita Is A Small Coastal Community Near Ventura, CA. In 1991, area approach was used to control debris flow in Laogan Ravine. area, having different type of diverse topography and complex geological conditions, where geological calamities occur frequently The mechanism of the rapid deep-seated landslides is examined through a series, Geomorphological information can be combined with decision-support tools to assess landslide hazard and risk. The Po Plain has harsh winters with long periods of subfreezing temperatures and warm sultry summers, with, Landslides in volcanic mountainous terrains covered by poorly consolidated materials are common in Mexico. the north of China to form a stationary front, which brings continuous storm, causing floods and geological calamities. Privacy It is shown that the conventional theory is physically unrealistic for flowing snow modeled as a frictional material. The area upstream of the landslide dam is submerged under water and the downstream area is flooded when the landslide dam breaks. La Conchita landslide on January 10, 2005 was a remobilization of a larger slump from 1995. The urgent need to improve debris flow disaster reduction is best met by modifying human systems, in particular removing people and assets from areas likely to be affected by debris flows. The results showed that the landslide area, mean sliding depth, and volume of the landslide in Hongye Village were approximately 4.5 ha, 5.1 m, and 22.8•104 m3, respectively. 75 other residences were evacuated after the slide. PART 4: LA CONCHITA CASE STUDY 27. The 2005 La Conchita Landslide Overview In 2005, the small town of La Conchita, California experienced a dangerous landslide event. The January 10, 2005 La Conchita landslide was the deadliest single event triggered by the 2004-2005 storm sequence. The La Conchita landslides that occurred in 1995 and 2005 form only a small percent of a much larger landslide complex, according to the geologists. You can request the full-text of this article directly from the authors on ResearchGate. rainfall more common in winter.Geomorphic instability processes are very common. Velocities of the surge fronts ranged from a few to nearly 15 feet per second and averaged close to 10 feet per second during the more fluid phases. The community lies on a narrow strip of land about 250 meters (820 feet) wide between the shoreline and abutting a … He said the remaining houses are in … During the flood season, while the rainfall intensity Appeal Analysis BACKGROUND Heavy rains of January 1995 led to a March 4, 1995, landslide in the LaConchita Ranch Community in Ventura County (County), California, covering 300 feet of Vista Del Rincon (VDR) Drive with 7-8 feet of mud and debris. Landslide areas were mapped in detail to classify the different failure types and parts. The total volume of loose solid matter of Sanyanyu valley is about 40 794 200 m3, which can convert to debris flow nearly 26 445 400 m3 (64. By viewing the case study photographs provided in lab and in Figure 12.5, answer the following questions. The hazard map was then divided by two scales, one with three classes for disaster managers and one with 10 detailed hazard classes for technical staff. The following summary of the 1995 La Conchita landslide is extracted from O'Tousa (1995) and Anderson (Robert Anderson, RJR Engineering, 2005, personal commun.). This condition most probably influences the landslide initiation in the two case studies. At the same time this essay will contribute to the study of geological disaster such as earthquake ,landslide and debris flow. The landslide is compared with other terrestrial mass movements on the basis of morphology, sedimentology, log(volume) versus fall height –runout length (H/L) relations and estimated Bingham plastic yield strength. September 15, 2016, was investigated. The volcano is prone to landslides due to its loose vulcanoclastic sediments that are dragged by the streams and torrents during the rainy season. 2). In the need of preventing and reducing geological calamities in the future, the status quo, characteristics Figure 5: Essentially the same tragedy strikes La Concitas (Conchita) a decade after the first landslide. Landslide case study Cantata La Contain is a very small community, located on the southern California coastline between Ventura and Santa Barbara. The model domain consisted of 25,614 square grid cells, each measuring 1.52 m on a side, and was developed