Failure modes and mechanisms of shallow debris landslides. Landslides landslides are defined as mass movement of rock, debris or earth down a slope and have come to include broad range of motions whereby falling, sliding and flowing under the influence of gravity dislodges earth material. This figure was based on the data obtained by many researchers until may 19, 2011 and was provided by the national research institute for earth science and disaster prevention nied. Abstractunderstanding the causes of slope development, particularly the initiation of movement, requires knowledge of a set of factors, usually associated with groundwater, that are often difficult to determine. Rainfall induced landslides in december 2004 in southwestern.
Monsoon and cycloneinduced rainfall are said to be major causes of landslides and land collapses, including riverbank erosion, in bangladeshs hill districts, particularly the chittagong region and parts of sylhet. This analysis should help predict more accurately landslide event sizes, both in terms of potential numbers and affected area. A total of 5858 rainfallinduced landslides were identified in the koshi river basin. Landslides can be triggered by both natural and man induced changes in the environment. Furthermore, a special session on earthquake induced landslides was again organized during the iaeg conference, which was held in turin in 2014. A database of earthquakeinduced landslides has been compiled which extends the work of keefer keefer dk. Gladeb a department of civil and environmental engineering, the hong kong university of science and technology, clear water bay, hong kong b department of geography and regional research, university of vienna, universitaetsstr. Mitigation concepts and approaches vulnerability to landslide hazards is a function of a sites location topography, geology, drainage, type of activity, and frequency of past landslides. Spatial distributions of earthquakeinduced landslides and hillslope preconditioning in the northwest south island. Some weeks ago we published a new study on the classification of earthquakeinduced landslide event sizes based on seismotectonic, topographic, climatic and geologic factors. Comparing the landslide size with rainfall conditions, this study found that large and deep landslides usually occurred due to longduration and moderateintensity rainfall 11. For the main part seismically generated landslides usually do not differ in their morphology and internal processes from those generated under nonseismic conditions.
Earthquake induced landslides lessons from taiwan and pakistan. Earthquake induced landslides lessons from taiwan and pakistan david petley 26th august 2008. Falls falls are abrupt movements of masses of geologic materials that become detached from steep slopes or cliffs figures 8a, b. Growing problem remains largely ignored despite risks to. Causes and types of landslides what is a landslide.
Can be extremely damaging to structures, roads, and lifelines but are not. Many rainfall induced landslides transform into debris flows fastmoving slurries of water, soil, and rock as they travel down steep slopes. Rainfallinduced landslides and debris flows in mengdong. Overview of landslide tools pdf 290 kb a brief overview of tools 2. While landslides are considered naturally occurring disasters, humaninduced changes in the environment have recently caused their upsurge. Human activity causes increase in landslides india. Location of the study area, with china seismic intensity scale of wenchuan earthquake. Rainfall and earthquakeinduced landslide susceptibility. Causes of landslides geological weak material erosion intense rainfall human excavation earthquake shaking volcanic eruption prepared by ct. Conceptual sketch of a seismicallyinduced lateral spread emanating from the eastern escarpment of crowleys ridge in eastern arkansas and southeastern missouri. Landslides growing problem remains largely ignored despite risks to life, property. Bulletin of the geological society of america 1984.
A powerpoint presentation on earthquakeinduced landslides. Rainfall induced landslide probability mapping for central. Mudslides like this one are the fastestmoving type of landslide, or mass wasting. Boundary effects of rainfallinduced landslides request pdf. Cambridge core geomorphology and physical geography landslides edited by john j. His blog provides a commentary on landslide events occurring worldwide, including the landslides themselves, latest research, and conferences and meetings. All geological zones of nepal were evaluated from the landslide occurrence perspective. This inventory has a lim itation that a landslide that occurred.
Pdf humaninduced landslides hil refer to landslide events that are directly triggered or partially aggravated by anthropic activities. Roman numerals vixi represent the earthquake magnitude contours. Landslides can occur without having a significant effect on any resource. The most abundant types of earthquakeinduced landslides are rock falls and slides of rock fragments that form on steep slopes. The main aim of this study is to develop a rainfall induced landslide probability map for kenyas central. This paper particularly discusses the issues related to the rainfall induced landslides in the nepal himalaya. Li et al rainfall and earthquakeinduced landslide susceptibility assessment 2721 fig. General information on the causes of rainfallinduced landslides pdf 483 kb.
Pdf risk assessment of snowmelt induced landslides based. Landslides are also known as landslips, slumps or slope failure. Given the number of deadly landslides, 2019 is the. Landslides occur often due to the earth quakes, floods and volcanic activities and in turn may lead to subsequent hazards. Causes of landslidinggeologists use a variety of classificationschemes to describe causes of landslides. The 2011 japan tsunami, which killed up to 20,000 people and caused the partial meltdown of the fukushima nuclear plant, was made worse by.
Pdf human induced landslides hil refer to landslide events that are directly triggered or partially aggravated by anthropic activities. Dave petley, provicechancellor at the university of sheffield it was shown that 463 nonseismic fatal landslides occurred last year, causing 3 270 deaths. Papers dealing with rainfall induced landslides, including the identification of rainfall thresholds for the possible initiation of landslides. In an analysis of the landslide database for 2019 by dr. Toward the analysis of anthropogenic changes of the. The primary regions of landslide occurrence and potential are the coastal and mountainous areas of california, oregon, and washington, the states comprising the intermountain west, and the mountainous. The effects of landslides on people and structures can be lessened by total avoidance. Types of landslides the most common types of landslides are des cribed below. Of the total landslides, about 31 were humaninduced and 9 were natural. For example, an earthquake induced landslide may lead to a deadly tsunami, if sufficient landslide material slides into the water body, displacing the water present. Dave petley is the provicechancellor research and innovation at the university of sheffield in the united kingdom. Boundary effects of rainfallinduced landslides article in computers and geotechnics 61. Model testing on rainfallinduced landslide of loose soil.
Classification of earthquakeinduced landslide event sizes. Landslide causes and triggering mechanisms highland, l. Mudslides can move at speeds of 80 kilometers 50 miles. The most frequent and widespread damaging landslides in the u. Because of wide variety of causes, nosingle scheme has yet been. Pdf rainfallinduced landslides in nepal semantic scholar. When landslides become debris flowstorrents, they can have both negative and positive effects on fish habitat. The distribution of the landslides caused by the main shock and the aftershocks on march 12 and april 11 is shown in fig. They refer to the movement of rock, debris or earth down a. It also highlights that some occurrences, especially those very far from the hypocentreactivated fault, cannot be. However, if people are exposed along their path, debris flows and torrents can only have negative effects and pose a risk to these people.
Characteristics of earthquake and raininduced landslides near the epicenter of wenchuan earthquake s. A landslide is the movement of rock, earth, or debris down a sloped section of land. The term landslide is used to describe a wide variety of processes that result in the perceptible downward and outward movement of soil, rock, and vegetation under gravitational influence. Earthquakeinduced landslides, sichuan province, china, may 12, 2008. Landslide types and processes printed on recycled paper l andslides in the united states occur in all 50 states. The categories are ranked, with category 6 rating categories of waterinduced landslide susceptibility susceptibility rating and explanation. A flume experiment was conducted to successfully initiate shallow debris landslides using artificial rainfall in zhouzhi county, qinba mountain. Rainfall induced landslide probability mapping for central province mercy mwaniki, thomas ngigi, and edward waithaka department of geomatic engineering and geospatial information systems gegis jomo kenyatta university of agriculture and technology p. During field survey, about 40 landslides were noticed in the reserve figure 7. This paper describes a general method for determining the amount of earthquakeinduced landsliding that occurs in a seismically active region over time. Spatial distributions of earthquakeinduced landslides and hillslope. The japan landslide society jls therefore organized a meeting fully dedicated to the research area of earthquake induced landslides. The susceptibility categories represent the nature and relative degree of hazard for waterinduced landslides and related slope failures in the study area. The landslide handbook a guide to understanding landslides.
Debris landslides in the shallow layer make up a large proportion of all landslides. Rainfall induced landslides geomorphology research group. On monday i gave a presentation to staff and students at the state key laboratory for geohazards at chengdu university of technology the topic was the lessons that can be learnt about earthquakeinduced landslides from the. Partial landslide prompts evacuations, damages home in south pasadenaa water leak is causing part of a hillside driveway to sink, and it has led. Although the causes of landslides are wide ranging, they have 2 aspects in common. This landslide left behind a trail of roots that now serve as a memorial for the foliage that once covered this area. These definitions are based mainly on the work of varnes 1978. Dogami interpretive map ims6, waterinduced landslide. Of the total landslides, about 31 were human induced and 9 were natural. Lateral spreads are triggered by liquefaction of cohesionless soils at. Our idea was that this classification could be used to help improve seismic hazard assessment by contributing to a better prediction of landslide hazards induced by an.
These types of slides can also be earthquakeinduced. Past earthquakes play a role in future landslides, research suggests. Characteristics of earthquake and raininduced landslides. However, they tend to be more widespread and sudden.
The threat of landslides like this have made the long drive to wenchuan a risky affair for rescuers. Movement occurs by freefall, bouncing, and rolling. The majority of rainfall induced landslides are shallow less than a few meters deep, small, and move rapidly. A very interesting fact can be seen that almost all the landslides which are documented are natural table 7. Based on the results of the test, we update the existing landslide hazards and risk scenario for extremely rapid landslides, mostly rock falls, and.
Rainfall induced landslides are a frequent and often catastrophic geological disaster, and the development of accurate early warning systems for such events is a primary challenge in the field of. This study analyzed the size of 172 rainfallinduced landslides in taiwan during 20062012. Landslides triggered by rainfall are a major multiple geological hazard on qinba mountain. Causes, effects and types of landslides earth eclipse. The rainfall induced landslides in the nepal himalaya extend tremendous damage to lives, property, infrastructure, and environment, particularly in the monsoon season. All the human induced landslides have recent origin. Then, the hazard grade of snowmelt induced landslides is predicted and classified by the calculation results of esm. The symposium covers all aspects of earthquakeinduced landslides including the phenomena occurred in manmade embankments as well as in natural slopes in mountainous areas.
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