Landslide

The term landslide or less frequently, landslip,[1] refers to several forms of mass wasting that include a wide range of ground movements, such as rockfalls, deep-seated slope failures, mudflows, and debris flows. Landslides occur in a variety of environments, characterized by either steep or gentle slope gradients, from mountain ranges to coastal cliffs or even underwater, in which case they are called submarine landslides. Gravity is the primary driving force for a landslide to occur, but there are other factors affecting slope stability that produce specific conditions that make a slope prone to failure. In many cases, the landslide is triggered by a specific event (such as a heavy rainfall, an earthquake, a slope cut to build a road, and many others), although this is not always identifiable.

Landslide in Cusco, Peru - 2018
A landslide near Cusco, Peru in 2018.
A NASA model has been developed to look at how potential landslide activity is changing around the world.

Causes

Mameyes
The Mameyes Landslide, in the Mameyes neighborhood of barrio Portugués Urbano in Ponce, Puerto Rico, which buried more than 100 homes, was caused by extensive accumulation of rains and, according to some sources, lightning.

Landslides occur when the slope (or a portion of it) undergoes some processes that change its condition from stable to unstable. This is essentially due to a decrease in the shear strength of the slope material, to an increase in the shear stress borne by the material, or to a combination of the two. A change in the stability of a slope can be caused by a number of factors, acting together or alone. Natural causes of landslides include:

  • saturation by rain water infiltration, snow melting, or glaciers melting;
  • rising of groundwater or increase of pore water pressure (e.g. due to aquifer recharge in rainy seasons, or by rain water infiltration);[2]
  • increase of hydrostatic pressure in cracks and fractures;[2][3]
  • loss or absence of vertical vegetative structure, soil nutrients, and soil structure (e.g. after a wildfire – a fire in forests lasting for 3–4 days);
  • erosion of the toe of a slope by rivers or ocean waves;
  • physical and chemical weathering (e.g. by repeated freezing and thawing, heating and cooling, salt leaking in the groundwater or mineral dissolution);[4][5]
  • ground shaking caused by earthquakes, which can destabilize the slope directly (e.g., by inducing soil liquefaction) or weaken the material and cause cracks that will eventually produce a landslide;[3][6][7]
  • volcanic eruptions;

Landslides are aggravated by human activities, such as:

Landslide in Sweden (Surte) 1950, 2
The landslide at Surte in Sweden, 1950. It was a quick clay slide killing one person.

Types

Debris flow

Slope material that becomes saturated with water may develop into a debris flow or mud flow. The resulting slurry of rock and mud may pick up trees, houses and cars, thus blocking bridges and tributaries causing flooding along its path.

Debris flow is often mistaken for flash flood, but they are entirely different processes.

Muddy-debris flows in alpine areas cause severe damage to structures and infrastructure and often claim human lives. Muddy-debris flows can start as a result of slope-related factors and shallow landslides can dam stream beds, resulting in temporary water blockage. As the impoundments fail, a "domino effect" may be created, with a remarkable growth in the volume of the flowing mass, which takes up the debris in the stream channel. The solid–liquid mixture can reach densities of up to 2,000 kg/m3 (120 lb/cu ft) and velocities of up to 14 m/s (46 ft/s).[9][10] These processes normally cause the first severe road interruptions, due not only to deposits accumulated on the road (from several cubic metres to hundreds of cubic metres), but in some cases to the complete removal of bridges or roadways or railways crossing the stream channel. Damage usually derives from a common underestimation of mud-debris flows: in the alpine valleys, for example, bridges are frequently destroyed by the impact force of the flow because their span is usually calculated only for a water discharge. For a small basin in the Italian Alps (area 1.76 km2 (0.68 sq mi)) affected by a debris flow,[9] estimated a peak discharge of 750 m3/s (26,000 cu ft/s) for a section located in the middle stretch of the main channel. At the same cross section, the maximum foreseeable water discharge (by HEC-1), was 19 m3/s (670 cu ft/s), a value about 40 times lower than that calculated for the debris flow that occurred.

Earthflow

The Costa della Gaveta earthflow
The Costa della Gaveta earthflow in Potenza, Italy. Even though it moves just some mm/a[4] and is hardly visible, this landslide causes progressive damage to the national road, the national highway, a flyover and several houses that were built on it.
Slide-guerrero1
A rock slide in Guerrero, Mexico

An earthflow is the downslope movement of mostly fine-grained material. Earthflows can move at speeds within a very wide range, from as low as 1 mm/yr (0.039 in/yr)[4][5] to 20 km/h (12.4 mph). Though these are a lot like mudflows, overall they are more slow moving and are covered with solid material carried along by flow from within. They are different from fluid flows which are more rapid. Clay, fine sand and silt, and fine-grained, pyroclastic material are all susceptible to earthflows. The velocity of the earthflow is all dependent on how much water content is in the flow itself: the higher the water content in the flow, the higher the velocity will be.

These flows usually begin when the pore pressures in a fine-grained mass increase until enough of the weight of the material is supported by pore water to significantly decrease the internal shearing strength of the material. This thereby creates a bulging lobe which advances with a slow, rolling motion. As these lobes spread out, drainage of the mass increases and the margins dry out, thereby lowering the overall velocity of the flow. This process causes the flow to thicken. The bulbous variety of earthflows are not that spectacular, but they are much more common than their rapid counterparts. They develop a sag at their heads and are usually derived from the slumping at the source.

Earthflows occur much more during periods of high precipitation, which saturates the ground and adds water to the slope content. Fissures develop during the movement of clay-like material which creates the intrusion of water into the earthflows. Water then increases the pore-water pressure and reduces the shearing strength of the material.[11]

Debris slide

Goodell Creek Debris Avalanche
Goodell Creek Debris Avalanche, Washington, USA

A debris slide is a type of slide characterized by the chaotic movement of rocks, soil, and debris mixed with water and/or ice. They are usually triggered by the saturation of thickly vegetated slopes which results in an incoherent mixture of broken timber, smaller vegetation and other debris.[11] Debris avalanches differ from debris slides because their movement is much more rapid. This is usually a result of lower cohesion or higher water content and commonly steeper slopes.

Steep coastal cliffs can be caused by catastrophic debris avalanches. These have been common on the submerged flanks of ocean island volcanos such as the Hawaiian Islands and the Cape Verde Islands.[12] Another slip of this type was Storegga landslide.

Debris slides generally start with big rocks that start at the top of the slide and begin to break apart as they slide towards the bottom. This is much slower than a debris avalanche. Debris avalanches are very fast and the entire mass seems to liquefy as it slides down the slope. This is caused by a combination of saturated material, and steep slopes. As the debris moves down the slope it generally follows stream channels leaving a v-shaped scar as it moves down the hill. This differs from the more U-shaped scar of a slump. Debris avalanches can also travel well past the foot of the slope due to their tremendous speed.[13]

Hunza River
Blockade of Hunza river

Rock avalanche

A rock avalanche, sometimes referred to as sturzstrom, is a type of large and fast-moving landslide. It is rarer than other types of landslides and therefore poorly understood. It exhibits typically a long run-out, flowing very far over a low angle, flat, or even slightly uphill terrain. The mechanisms favoring the long runout can be different, but they typically result in the weakening of the sliding mass as the speed increases.[14][15][16]

Shallow landslide

Limone sul Garda Hotel 001
Hotel Panorama at Lake Garda. Part of a hill of Devonian shale was removed to make the road, forming a dip-slope. The upper block detached along a bedding plane and is sliding down the hill, forming a jumbled pile of rock at the toe of the slide.

A landslide in which the sliding surface is located within the soil mantle or weathered bedrock (typically to a depth from few decimeters to some meters) is called a shallow landslide. They usually include debris slides, debris flow, and failures of road cut-slopes. Landslides occurring as single large blocks of rock moving slowly down slope are sometimes called block glides.

Shallow landslides can often happen in areas that have slopes with high permeable soils on top of low permeable bottom soils. The low permeable, bottom soils trap the water in the shallower, high permeable soils creating high water pressure in the top soils. As the top soils are filled with water and become heavy, slopes can become very unstable and slide over the low permeable bottom soils. Say there is a slope with silt and sand as its top soil and bedrock as its bottom soil. During an intense rainstorm, the bedrock will keep the rain trapped in the top soils of silt and sand. As the topsoil becomes saturated and heavy, it can start to slide over the bedrock and become a shallow landslide. R. H. Campbell did a study on shallow landslides on Santa Cruz Island, California. He notes that if permeability decreases with depth, a perched water table may develop in soils at intense precipitation. When pore water pressures are sufficient to reduce effective normal stress to a critical level, failure occurs.[17]

Deep-seated landslide

Kihotown Sehara Miepref No,3
Deep-seated landslide on a mountain in Sehara, Kihō, Japan caused by torrential rain of Tropical Storm Talas
Landslide 2
Landslide of soil and regolith in Pakistan

Deep-seated landslides are those in which the sliding surface is mostly deeply located below the maximum rooting depth of trees (typically to depths greater than ten meters). They usually involve deep regolith, weathered rock, and/or bedrock and include large slope failure associated with translational, rotational, or complex movement. This type of landslide potentially occurs in an tectonic active region like Zagros Mountain in Iran. These typically move slowly, only several meters per year, but occasionally move faster. They tend to be larger than shallow landslides and form along a plane of weakness such as a fault or bedding plane. They can be visually identified by concave scarps at the top and steep areas at the toe.[18]

Causing tsunamis

Landslides that occur undersea, or have impact into water e.g. significant rockfall or volcanic collapse into the sea,[19] can generate tsunamis. Massive landslides can also generate megatsunamis, which are usually hundreds of meters high. In 1958, one such tsunami occurred in Lituya Bay in Alaska.[12][20]

Related phenomena

  • An avalanche, similar in mechanism to a landslide, involves a large amount of ice, snow and rock falling quickly down the side of a mountain.
  • A pyroclastic flow is caused by a collapsing cloud of hot ash, gas and rocks from a volcanic explosion that moves rapidly down an erupting volcano.

Landslide prediction mapping

Landslide hazard analysis and mapping can provide useful information for catastrophic loss reduction, and assist in the development of guidelines for sustainable land-use planning. The analysis is used to identify the factors that are related to landslides, estimate the relative contribution of factors causing slope failures, establish a relation between the factors and landslides, and to predict the landslide hazard in the future based on such a relationship.[21] The factors that have been used for landslide hazard analysis can usually be grouped into geomorphology, geology, land use/land cover, and hydrogeology. Since many factors are considered for landslide hazard mapping, GIS is an appropriate tool because it has functions of collection, storage, manipulation, display, and analysis of large amounts of spatially referenced data which can be handled fast and effectively.[22] Cardenas reported evidence on the exhaustive use of GIS in conjunction of uncertainty modelling tools for landslide mapping.[23][24] Remote sensing techniques are also highly employed for landslide hazard assessment and analysis. Before and after aerial photographs and satellite imagery are used to gather landslide characteristics, like distribution and classification, and factors like slope, lithology, and land use/land cover to be used to help predict future events.[25] Before and after imagery also helps to reveal how the landscape changed after an event, what may have triggered the landslide, and shows the process of regeneration and recovery.[26]

Using satellite imagery in combination with GIS and on-the-ground studies, it is possible to generate maps of likely occurrences of future landslides.[27] Such maps should show the locations of previous events as well as clearly indicate the probable locations of future events. In general, to predict landslides, one must assume that their occurrence is determined by certain geologic factors, and that future landslides will occur under the same conditions as past events.[28] Therefore, it is necessary to establish a relationship between the geomorphologic conditions in which the past events took place and the expected future conditions.[29]

Natural disasters are a dramatic example of people living in conflict with the environment. Early predictions and warnings are essential for the reduction of property damage and loss of life. Because landslides occur frequently and can represent some of the most destructive forces on earth, it is imperative to have a good understanding as to what causes them and how people can either help prevent them from occurring or simply avoid them when they do occur. Sustainable land management and development is also an essential key to reducing the negative impacts felt by landslides.

SlideMinder Extensometer
A Wireline extensometer monitoring slope displacement and transmitting data remotely via radio or Wi-Fi. In situ or strategically deployed extensometers may be used to provide early warning of a potential landslide.[30]

GIS offers a superior method for landslide analysis because it allows one to capture, store, manipulate, analyze, and display large amounts of data quickly and effectively. Because so many variables are involved, it is important to be able to overlay the many layers of data to develop a full and accurate portrayal of what is taking place on the Earth's surface. Researchers need to know which variables are the most important factors that trigger landslides in any given location. Using GIS, extremely detailed maps can be generated to show past events and likely future events which have the potential to save lives, property, and money.

Global Landslide Risks

Global landslide risks

Rock slide detector UPRR Sierra grade at "Cape Horn", Colfax, CA

Trackside rock slide detector on the UPRR Sierra grade near Colfax, CA

Prehistoric landslides

Rhine cutting through Flims Rockslide debris
Rhine cutting through Flims Rockslide debris, Switzerland
  • Storegga Slide, some 8,000 years ago off the western coast of Norway. Caused massive tsunamis in Doggerland and other countries connected to the North Sea. A total volume of 3,500 km3 (840 cu mi) debris was involved; comparable to a 34 m (112 ft) thick area the size of Iceland. The landslide is thought to be among the largest in history.
  • Landslide which moved Heart Mountain to its current location, the largest continental landslide discovered so far. In the 48 million years since the slide occurred, erosion has removed most of the portion of the slide.
  • Flims Rockslide, ca. 12 km3 (2.9 cu mi), Switzerland, some 10000 years ago in post-glacial Pleistocene/Holocene, the largest so far described in the alps and on dry land that can be easily identified in a modestly eroded state.[31]
  • The landslide around 200 BC which formed Lake Waikaremoana on the North Island of New Zealand, where a large block of the Ngamoko Range slid and dammed a gorge of Waikaretaheke River, forming a natural reservoir up to 256 metres (840 ft) deep.
  • Cheekye Fan, British Columbia, Canada, ca. 25 km2 (9.7 sq mi), Late Pleistocene in age.
  • The Manang-Braga rock avalanche/debris flow may have formed Marsyangdi Valley in the Annapurna Region, Nepal, during an interstadial period belonging to the last glacial period.[32] Over 15 km3 of material are estimated to have been moved in the single event, making it one of the largest continental landslides.
  • A massive slope failure 60 km north of Kathmandu Nepal, involving an estimated 10–15 km3.[33] Prior to this landslide the mountain may have been the world's 15th mountain above 8000m.

Historical landslides

Extraterrestrial landslides

Venus-Landslide
Before and after radar images of a landslide on Venus. In the center of the image on the right, the new landslide, a bright, flow-like area, can be seen extending to the left of a bright fracture. 1990 image.
Avalanche on Mars February 19th 2008 01
Landslide in progress on Mars, 2008-02-19

Evidence of past landslides has been detected on many bodies in the solar system, but since most observations are made by probes that only observe for a limited time and most bodies in the solar system appear to be geologically inactive not many landslides are known to have happened in recent times. Both Venus and Mars have been subject to long-term mapping by orbiting satellites, and examples of landslides have been observed on both planets.

See also

References

  1. ^ "Landslide synonyms". www.thesaurus.com. Roget's 21st Century Thesaurus. 2013. Retrieved 16 March 2018.
  2. ^ a b Hu, Wei; Scaringi, Gianvito; Xu, Qiang; Van Asch, Theo W. J. (2018-04-10). "Suction and rate-dependent behaviour of a shear-zone soil from a landslide in a gently-inclined mudstone-sandstone sequence in the Sichuan basin, China". Engineering Geology. 237: 1–11. doi:10.1016/j.enggeo.2018.02.005. ISSN 0013-7952.
  3. ^ a b Fan, Xuanmei; Xu, Qiang; Scaringi, Gianvito (2017-12-01). "Failure mechanism and kinematics of the deadly June 24th 2017 Xinmo landslide, Maoxian, Sichuan, China". Landslides. 14 (6): 2129–2146. doi:10.1007/s10346-017-0907-7. ISSN 1612-5118.
  4. ^ a b c Di Maio, Caterina; Vassallo, Roberto; Scaringi, Gianvito; De Rosa, Jacopo; Pontolillo, Dario Michele; Maria Grimaldi, Giuseppe (2017-11-01). "Monitoring and analysis of an earthflow in tectonized clay shales and study of a remedial intervention by KCl wells". Rivista Italiana di Geotecnica. 51 (3): 48–63. doi:10.19199/2017.3.0557-1405.048.
  5. ^ a b Di Maio, Caterina; Scaringi, Gianvito; Vassallo, R (2014-01-01). "Residual strength and creep behaviour on the slip surface of specimens of a landslide in marine origin clay shales: influence of pore fluid composition". Landslides. 12 (4): 657–667. doi:10.1007/s10346-014-0511-z.
  6. ^ Fan, Xuanmei; Scaringi, Gianvito; Domènech, Guillem; Yang, Fan; Guo, Xiaojun; Dai, Lanxin; He, Chaoyang; Xu, Qiang; Huang, Runqiu (2019-01-09). "Two multi-temporal datasets that track the enhanced landsliding after the 2008 Wenchuan earthquake". Earth System Science Data. 11 (1): 35–55. Bibcode:2019ESSD...11...35F. doi:10.5194/essd-11-35-2019. ISSN 1866-3508.
  7. ^ Fan, Xuanmei; Xu, Qiang; Scaringi, Gianvito (2018-01-26). "Brief communication: Post-seismic landslides, the tough lesson of a catastrophe". Natural Hazards and Earth System Sciences. 18 (1): 397–403. Bibcode:2018NHESS..18..397F. doi:10.5194/nhess-18-397-2018. ISSN 1561-8633.
  8. ^ Fan, Xuanmei; Xu, Qiang; Scaringi, Gianvito (2018-10-24). "The "long" runout rock avalanche in Pusa, China, on August 28, 2017: a preliminary report". Landslides. 16: 139–154. doi:10.1007/s10346-018-1084-z. ISSN 1612-5118.
  9. ^ a b Chiarle, Marta; Luino, Fabio (1998). "Colate detritiche torrentizie sul Monte Mottarone innescate dal nubifragio dell'8 luglio 1996". La prevenzione delle catastrofi idrogeologiche. Il contributo della ricerca scientifica (conference book). pp. 231–245.
  10. ^ Arattano, Massimo (2003). "Monitoring the presence of the debris flow front and its velocity through ground vibration detectors". Third International Conference on Debris-flow Hazards Mitigation: Mechanics, Prediction, and Assessment (debris flow): 719–730.
  11. ^ a b Easterbrook, Don J. (1999). Surface Processes and Landforms. Upper Saddle River: Prentice-Hall. ISBN 978-0-13-860958-0.
  12. ^ a b Le Bas, T.P. (2007), "Slope Failures on the Flanks of Southern Cape Verde Islands", in Lykousis, Vasilios (ed.), Submarine mass movements and their consequences: 3rd international symposium, Springer, ISBN 978-1-4020-6511-8
  13. ^ Schuster, R.L. & Krizek, R.J. (1978). Landslides: Analysis and Control. Washington, D.C.: National Academy of Sciences.
  14. ^ Hu, Wei; Scaringi, Gianvito; Xu, Qiang; Huang, Runqiu (2018-06-05). "Internal erosion controls failure and runout of loose granular deposits: Evidence from flume tests and implications for post-seismic slope healing". Geophysical Research Letters. 45 (11): 5518. Bibcode:2018GeoRL..45.5518H. doi:10.1029/2018GL078030.
  15. ^ Hu, Wei; Xu, Qiang; Wang, Gonghui; Scaringi, Gianvito; McSaveney, Mauri; Hicher, Pierre-Yves (2017-10-31). "Shear Resistance Variations in Experimentally Sheared Mudstone Granules: A Possible Shear-Thinning and Thixotropic Mechanism". Geophysical Research Letters. 44 (21): 11, 040. Bibcode:2017GeoRL..4411040H. doi:10.1002/2017GL075261.
  16. ^ Scaringi, Gianvito; Hu, Wei; Xu, Qiang; Huang, Runqiu (2017-12-20). "Shear-Rate-Dependent Behavior of Clayey Bimaterial Interfaces at Landslide Stress Levels". Geophysical Research Letters. 45 (2): 766. Bibcode:2018GeoRL..45..766S. doi:10.1002/2017GL076214.
  17. ^ Renwick, W.; Brumbaugh, R.; Loeher, L (1982). "Landslide Morphology and Processes on Santa Cruz Island California". Geografiska Annaler. Series B, Physical Geography. 64 (3/4): 149–159. doi:10.2307/520642. JSTOR 520642.
  18. ^ Johnson, B.F. (June 2010). "Slippery slopes". Earth magazine. pp. 48–55.
  19. ^ "Ancient Volcano Collapse Caused A Tsunami With An 800-Foot Wave". Popular Science. Retrieved 2017-10-20.
  20. ^ Mitchell, N (2003). "Susceptibility of mid-ocean ridge volcanic islands and seamounts to large scale landsliding". Journal of Geophysical Research. 108 (B8): 1–23. Bibcode:2003JGRB..108.2397M. doi:10.1029/2002jb001997.
  21. ^ Chen, Zhaohua; Wang, Jinfei (2007). "Landslide hazard mapping using logistic regression model in Mackenzie Valley, Canada". Natural Hazards. 42: 75–89. doi:10.1007/s11069-006-9061-6.
  22. ^ Clerici, A; Perego, S; Tellini, C; Vescovi, P (2002). "A procedure for landslide susceptibility zonation by the conditional analysis method1". Geomorphology. 48 (4): 349–364. Bibcode:2002Geomo..48..349C. doi:10.1016/S0169-555X(02)00079-X.
  23. ^ Cardenas, IC (2008). "Landslide susceptibility assessment using Fuzzy Sets, Possibility Theory and Theory of Evidence. Estimación de la susceptibilidad ante deslizamientos: aplicación de conjuntos difusos y las teorías de la posibilidad y de la evidencia". Ingenieria e Investigación. 28 (1).
  24. ^ Cardenas, IC (2008). "Non-parametric modeling of rainfall in Manizales City (Colombia) using multinomial probability and imprecise probabilities. Modelación no paramétrica de lluvias para la ciudad de Manizales, Colombia: una aplicación de modelos multinomiales de probabilidad y de probabilidades imprecisas". Ingenieria e Investigación. 28 (2).
  25. ^ Metternicht, G; Hurni, L; Gogu, R (2005). "Remote sensing of landslides: An analysis of the potential contribution to geo-spatial systems for hazard assessment in mountainous environments". Remote Sensing of Environment. 98 (2–3): 284–303. Bibcode:2005RSEnv..98..284M. doi:10.1016/j.rse.2005.08.004.
  26. ^ De La Ville, Noemi; Chumaceiro Diaz, Alejandro; Ramirez, Denisse (2002). "Remote Sensing and GIS Technologies as Tools to Support Sustainable Management of Areas Devastated by Landslides" (PDF). Environment, Development and Sustainability. 4 (2): 221–229. doi:10.1023/A:1020835932757.
  27. ^ Fabbri, Andrea G.; Chung, Chang-Jo F.; Cendrero, Antonio; Remondo, Juan (2003). "Is Prediction of Future Landslides Possible with a GIS?". Natural Hazards. 30 (3): 487–503. doi:10.1023/B:NHAZ.0000007282.62071.75.
  28. ^ Lee, S; Talib, Jasmi Abdul (2005). "Probabilistic landslide susceptibility and factor effect analysis". Environmental Geology. 47 (7): 982–990. doi:10.1007/s00254-005-1228-z.
  29. ^ Ohlmacher, G (2003). "Using multiple logistic regression and GIS technology to predict landslide hazard in northeast Kansas, USA". Engineering Geology. 69 (3–4): 331–343. doi:10.1016/S0013-7952(03)00069-3.
  30. ^ Rose & Hunger, "Forecasting potential slope failure in open pit mines", Journal of Rock Mechanics & Mining Sciences, February 17, 2006. August 20, 2015.
  31. ^ Weitere Erkenntnisse und weitere Fragen zum Flimser Bergsturz Archived 2011-07-06 at the Wayback Machine A.v. Poschinger, Angewandte Geologie, Vol. 11/2, 2006
  32. ^ Fort, Monique (2011). "Two large late quaternary rock slope failures and their geomorphic significance, Annapurna, Himalayas (Nepal)". Geografia Fisica e Dinamica Quaternaria. 34: 5–16.
  33. ^ Weidinger, Johannes T.; Schramm, Josef-Michael; Nuschej, Friedrich (2002-12-30). "Ore mineralization causing slope failure in a high-altitude mountain crest—on the collapse of an 8000 m peak in Nepal". Journal of Asian Earth Sciences. 21 (3): 295–306. Bibcode:2002JAESc..21..295W. doi:10.1016/S1367-9120(02)00080-9.
  34. ^ "Hope Slide". BC Geographical Names.
  35. ^ Peres, D. J.; Cancelliere, A. (2016-10-01). "Estimating return period of landslide triggering by Monte Carlo simulation". Journal of Hydrology. Flash floods, hydro-geomorphic response and risk management. 541: 256–271. Bibcode:2016JHyd..541..256P. doi:10.1016/j.jhydrol.2016.03.036.
  36. ^ "Large landslide in Gansu Zhouqu August 7". Easyseosolution.com. August 19, 2010. Archived from the original on August 24, 2010.
  37. ^ "Brazil mudslide death toll passes 450". Cbc.ca. January 13, 2011. Retrieved January 13, 2011.

External links

1894 United States elections

The 1894 United States elections was held on November 6, and elected the members of the 54th United States Congress. These were mid-term elections during Democratic President Grover Cleveland's second term. The Republican landslide of 1894 marked a realigning election In American politics as the nation moved from the Third Party System that had focused on issues of civil war and reconstruction, and entered the Fourth Party System, known as the Progressive Era, which focused on middle class reforms.The Democrats suffered a landslide defeat in the House losing over 100 seats to the Republicans in the single largest swing in the history of the House. The Democrats also lost four seats in the Senate, thus resulting in the President's party completely losing control of both houses of Congress, the first time this ever happened in a midterm election.

The Democratic Party losses can be traced largely to the Panic of 1893 and the ineffective party leadership of Cleveland. Republicans effectively used the issues of the tariff, bimetallism, and the Cuban War of Independence against Cleveland. The Democrats suffered huge defeats outside the South (almost ninety percent of Northeastern and Midwestern House Democrats lost re-election), and the Democratic Party underwent a major turnover in party leadership. With the defeat of many Bourbon Democrats, William Jennings Bryan took the party in a more populist direction starting with the 1896 elections.

1906 United Kingdom general election

The 1906 United Kingdom general election was held from 12 January to 8 February 1906.

The Liberals, led by Prime Minister Henry Campbell-Bannerman, won a landslide majority at the election. The Conservatives led by Arthur Balfour, who had been in government until the month before the election, lost more than half their seats, including party leader Balfour's own seat in Manchester East, leaving the party with its record fewest seats. The election saw a 5.4% swing from the Conservative Party to the Liberal Party, the largest-ever seen at the time (however, if only looking at seats contested in both 1900 and 1906, the Conservative vote fell by 11.6%). This has resulted in the 1906 general election being dubbed the "Liberal landslide", and is now ranked alongside the 1931, 1945, 1983 and 1997 general elections as one of the largest landslide election victories.The Labour Representation Committee was far more successful than at the 1900 general election and after the election would be renamed the Labour Party with 29 MPs and Keir Hardie as leader. The Irish Parliamentary Party, led by John Redmond, achieved its seats with a relatively low number of votes, as 73 candidates stood unopposed.

This election was a landslide defeat for the Conservative Party and their Liberal Unionist allies, with the primary reason given by historians as the party's weakness after its split over the issue of free trade (Joseph Chamberlain had resigned from government in September 1903 in order to campaign for Tariff Reform, which would allow "preferential tariffs"). Many working-class people at the time saw this as a threat to the price of food, hence the debate was nicknamed "Big Loaf, Little Loaf". The Liberals' landslide victory of 125 seats over all other parties led to the passing of social legislation known as the Liberal reforms.

This was the last general election in which the Liberals won an absolute majority in the House of Commons, and the last general election in which they won the popular vote. It was also the last peacetime election held more than five years after the previous one prior to passage of the Parliament Act 1911, which limited the duration of Parliaments in peacetime to five years. The Conservative Party's seat total of 156 MPs remains its worst result ever in a general election.

1976 United States presidential election in Massachusetts

The 1976 United States presidential election in Massachusetts took place on November 2, 1976, as part of the 1976 United States presidential election, which was held throughout all 50 states and D.C. Voters chose 14 representatives, or electors to the Electoral College, who voted for president and vice president.

Massachusetts voted for the Democratic nominee, Georgia Governor Jimmy Carter, over incumbent Republican President Gerald Ford of Michigan. Carter's running mate was Senator Walter Mondale of Minnesota, while Ford ran with Senator Bob Dole of Kansas.

Carter carried Massachusetts with 56.11% of the vote to Ford's 40.44%, a 15.67% margin of victory. In a distant third was Independent candidate Eugene McCarthy, a former Democratic Senator from Minnesota known for his anti-war activism, who took 2.58%.

As Carter narrowly defeated Ford nationally to win the presidency, Massachusetts weighed in as 13% more Democratic than the national average in the 1976 election.

Massachusetts had been a Democratic-leaning state since 1928, and a Democratic stronghold since 1960, so Carter's win was not unexpected. In 1972, Massachusetts was the only state in the nation to vote for Democrat George McGovern over Republican Richard Nixon in the latter's 49-state landslide. McGovern had carried Massachusetts 54–45, despite losing every other state in the midst of a massive Republican landslide.

Ford for his part performed relatively strongly in the state as a moderate Northern Republican, holding at just over 40% of the vote, while Carter gained only slightly over McGovern- even though Carter was winning nationally while McGovern was losing in a landslide. The state's capital and largest city, Boston, would be one of the few regions in the country where McGovern would actually perform more strongly than Carter in absolute terms. Suffolk County, where Boston is located, had voted for George McGovern in 1972 by a landslide of 66% versus Richard Nixon's 33%, but in 1976, Carter would only win the county with 61% versus Gerald Ford's 35%. Whereas McGovern had been very popular with urban social liberals in the Northeast in 1972, in 1976 many secular social liberals were turned off by the Southern & evangelical Christian Carter, and the Northern moderate Ford was seen as a preferable alternative to many of these voters in Boston. This is also the state with the most electoral votes that was decided by double digits.

In the 1960s, for three elections straight beginning with John F. Kennedy in 1960, Democrats had won landslides of over 60% of the vote, with Republicans failing to break 40%. Even in the GOP landslide of 1972, Massachusetts had clocked in as a whopping 32% more Democratic than the nation. Thus overall the results of 1976 indicated a slight Republican rebound in the state that would continue into the 1980s.

1983 United Kingdom general election

The 1983 United Kingdom general election was held on Thursday, 9 June 1983. It gave the Conservative Party under the leadership of Margaret Thatcher the most decisive election victory since that of the Labour Party in 1945.

Thatcher's first four years as Prime Minister had not been an easy time. Unemployment increased during the first three years of her premiership and the economy went through a recession. However, the British victory in the Falklands War led to a recovery of her personal popularity; the economy had also returned to growth. By the time Thatcher called the election in May 1983, the Conservatives were most people's firm favourites to win the general election. The resulting win earned the Conservatives their biggest parliamentary majority of the post-war era, and their second-biggest majority as a single-party government, behind only the 1924 election (they earned even more seats in the 1931 election, but were part of the National Government)The Labour Party had been led by Michael Foot since the resignation of former Prime Minister James Callaghan in 1980. They had fared well in opinion polls and local elections during this time, but issues developed which would lead directly to their defeat. Labour adopted a platform that was considered more left-wing than usual. Several moderate Labour MPs had defected from the party to form the Social Democratic Party (SDP); they then formed the SDP–Liberal Alliance with the existing Liberal Party.

The opposition vote split almost evenly between the Alliance and Labour. With its worst electoral performance since 1918, the Labour vote fell by over 3 million votes from 1979 and this accounted for both a national swing of almost 4% towards the Conservatives and their larger parliamentary majority of 144 seats, even though the Conservatives' total vote fell by almost 700,000. This was the last general election where a governing party increased its number of seats until 2015.

The Alliance finished in third place but came within 700,000 votes of out-polling Labour; by gaining 25.4% of the vote it won the largest percentage for any third party since sixty years prior. Despite this, they won only 23 seats, whereas Labour won 209. The Liberals argued that a proportional electoral system would have given them a more representative number of MPs. Changing the electoral system had been a long-running Liberal Party campaign plank and would later be adopted by the Liberal Democrats.

The election night was broadcast live on the BBC, and was presented by David Dimbleby, Sir Robin Day and Peter Snow. It was also broadcast on ITV, and presented by Alastair Burnet, Peter Sissons and Martyn Lewis.

Three future leaders of the Labour Party (Tony Blair, Gordon Brown and Jeremy Corbyn) were first elected at this election – two went on hold the office of Prime Minister, whilst Corbyn became Labour leader in 2015. Former Labour Prime Minister Harold Wilson, Shirley Williams, Bill Rodgers, Joan Lestor and Tony Benn left Parliament as a result of this election, although Benn would return in a by-election the following year, and Lestor at the following general election. In addition, two future Leaders of the Liberal Democrats were first elected (Paddy Ashdown and Charles Kennedy), and one of the Conservative Party (Michael Howard).

1997 Thredbo landslide

The Thredbo landslide was a catastrophic landslide that occurred at the village and ski resort of Thredbo, New South Wales, Australia, on 30 July 1997. Two ski lodges were destroyed and a total of 18 died.

2014 Oso mudslide

A major landslide occurred 4 miles (6.4 km) east of Oso, Washington, United States, on March 22, 2014, at 10:37 a.m. local time. A portion of an unstable hill collapsed, sending mud and debris to the south across the North Fork of the Stillaguamish River, engulfing a rural neighborhood, and covering an area of approximately 1 square mile (2.6 km2). Forty-three people were killed and 49 homes and other structures destroyed.

Bridge of the Gods (land bridge)

The Bridge of the Gods was a natural dam created by the Bonneville Slide, a major landslide that dammed the Columbia River near present-day Cascade Locks, Oregon in the Pacific Northwest of the United States. The river eventually breached the bridge and washed much of it away, but the event is remembered in local legends of the Native Americans as the Bridge of the Gods.

The Bridge of the Gods is also the name of a modern manmade bridge, across the Columbia River between Oregon and Washington.

Frank Slide

The Frank Slide was a rockslide that buried part of the mining town of Frank, Northwest Territories, Canada, at 4:10 a.m. on April 29, 1903. Around 110 million tonnes (121 million US tons) of limestone rock slid down Turtle Mountain. Witnesses reported that the rock had reached up the opposing hills within 100 seconds, obliterating the eastern edge of Frank, the Canadian Pacific Railway line and the coal mine. It was one of the largest landslides in Canadian history and remains the deadliest, as between 70 and 90 of the town's residents were killed, most of whom remain buried in the rubble. Multiple factors led to the slide: Turtle Mountain's formation left it in a constant state of instability. Coal mining operations may have weakened the mountain's internal structure, as did a wet winter and cold snap on the night of the disaster.

The railway was repaired within three weeks and the mine was quickly reopened. The section of town closest to the mountain was relocated in 1911 amid fears that another slide was possible. The town's population nearly doubled its pre-slide population by 1906, but dwindled after the mine closed permanently in 1917. The community is now part of the Municipality of Crowsnest Pass in the Province of Alberta and has a population around 200. The site of the disaster, which remains nearly unchanged since the slide, is now a popular tourist destination. It has been designated a Provincial Historic Site of Alberta and is home to an interpretive centre that receives over 100,000 visitors annually.

Great Hanshin earthquake

The Great Hanshin earthquake (阪神・淡路大震災, Hanshin Awaji daishinsai), or Kobe earthquake, occurred on January 17, 1995 at 05:46:53 JST (January 16 at 20:46:53 UTC) in the southern part of Hyōgo Prefecture, Japan, including the region known as Hanshin. It measured 6.9 on the moment magnitude scale and had a maximum intensity of 7 on the JMA Seismic Intensity Scale. The tremors lasted for approximately 20 seconds. The focus of the earthquake was located 17 km beneath its epicenter, on the northern end of Awaji Island, 20 km away from the center of the city of Kobe.

Up to 6,434 people lost their lives; about 4,600 of them were from Kobe. Among major cities, Kobe, with its population of 1.5 million, was the closest to the epicenter and hit by the strongest tremors. This was Japan's worst earthquake in the 20th century after the Great Kantō earthquake in 1923, which claimed more than 105,000 lives.

Lake San Cristobal

Lake San Cristobal is a lake in the U.S. state of Colorado. Located in the San Juan Mountains at an elevation of 9,003 feet (2,744 m), the freshwater lake is 2.1 miles (3.4 km) long, up to 89 feet (27 m) deep, has a surface area of 0.52 square miles (1.3 km2), and holds about 11,000 acre feet (14,000,000 m3) of water. The town of Lake City, a few miles to the north, is named after Lake San Cristobal. The name San Cristóbal means Saint Christopher in the Spanish language. Many old silver mines are near the lake and it is very clean and well kept, and stocked with Rainbow Trout.

Landslide (Fleetwood Mac song)

"Landslide" is a song written by Stevie Nicks and performed by British-American music group Fleetwood Mac. It was first featured on the band's self-titled 1975 album Fleetwood Mac. The original recording also appears on the compilation albums 25 Years – The Chain (1992) and The Very Best of Fleetwood Mac (2002), while a live version was released as a single 23 years later from the live reunion album The Dance. It reached number 51 on the Billboard Hot 100 chart and 10 on the Adult Contemporary chart. "Landslide" was certified Gold in October 2009 for sales of over 500,000 copies in the United States. According to Nielsen Soundscan, "Landslide" sold 1,315,950 copies in the United States as of February 2013.

Landslide dam

A landslide dam or barrier lake is a natural damming of a river by some kind of landslides, such as debris flows and rock avalanches, or by volcanic eruptions. If the damming landslides are caused by an earthquake, it may also be called a quake lake. Some landslide dams are as high as the largest existing artificial dam.

Landslide victory

A landslide victory is an electoral victory in a political system, when one candidate or party receives an overwhelming majority of the votes or seats in the elected body, thus all but utterly eliminating the opponents. The winning party has reached more voters than usual, and a landslide victory is often seen in hindsight as a turning point in people's views on political matters.

Part of the reason for a landslide victory is sometimes a bandwagon effect, as a significant number of people may decide to vote for the party which is in the lead in the pre-election opinion polls, regardless of its politics.

The term is borrowed from geology, where a landslide takes almost everything with it on its way.

Megatsunami

A megatsunami is a very large wave created by a large, sudden displacement of material into a body of water.

Megatsunamis have quite different features from other, more usual types of tsunamis. Most tsunamis are caused by underwater tectonic activity (movement of the earth's plates) and therefore occur along plate boundaries and as a result of earthquake and rise or fall in the sea floor, causing water to be displaced. Ordinary tsunamis have shallow waves out at sea, and the water piles up to a wave height of up to about 10 metres (33 feet) as the sea floor becomes shallow near land. By contrast, megatsunamis occur when a very large amount of material suddenly falls into water or anywhere near water (such as via a meteor impact), or are caused by volcanic activity. They can have extremely high initial wave heights of hundreds and possibly thousands of metres, far beyond any ordinary tsunami, as the water is "splashed" upwards and outwards by the impact or displacement. As a result, two heights are sometimes quoted for megatsunamis – the height of the wave itself (in water), and the height to which it surges when it reaches land, which depending upon the locale, can be several times larger.

Modern megatsunamis include the one associated with the 1883 eruption of Krakatoa (volcanic eruption), the 1958 Lituya Bay megatsunami (landslide into a bay), and the wave resulting from the Vajont Dam landslide (caused by human activity destabilizing sides of valley). Prehistoric examples include the Storegga Slide (landslide), and the Chicxulub, Chesapeake Bay and Eltanin meteor impacts.

Mudflow

A mudflow or mud flow is a form of mass wasting involving "very rapid to extremely rapid surging flow" of debris that has become partially or fully liquified by the addition of significant amounts of water to the source material.Mudflows contain a significant proportion of clay, which makes them more fluid than debris flows; thus, they are able to travel farther and across lower slope angles. Both types are generally mixtures of various kinds of materials of different sizes, which are typically sorted by size upon deposition.Mudflows are often called mudslides, a term applied indiscriminately by the mass media to a variety of mass wasting events. Mudflows often start as slides, becoming flows as water is entrained along the flow path; such events are often called flow slides.Other types of mudflows include lahars (involving fine-grained pyroclastic deposits on the flanks of volcanoes) and jökulhlaups (outbursts from under glaciers or icecaps).A statutory definition of "flood-related mudslide" appears in the United States' National Flood Insurance Act of 1968, as amended, codified at 42 USC Sections 4001 and following.

Psilocybe caerulescens

Psilocybe caerulescens, also known as Landslide mushroom ("derrumbe" in Spanish), is a psilocybin mushroom having psilocybin and psilocin as main active compounds. Along with Psilocybe mexicana and Psilocybe aztecorum, it is one of the mushrooms likely to have been used by the Aztecs and is currently used by Mazatec shamans for its entheogenic properties.

Thistle, Utah

Thistle is a ghost town in Spanish Fork Canyon in southeastern Utah County, Utah, United States. During the era of steam locomotives, the town's primary industry was servicing trains for the Denver and Rio Grande Western Railroad (often shortened to D&RG, D&RGW, or Rio Grande). The fortunes of the town were closely linked with those of the railroad until the changeover to diesel locomotives, when the town started to decline.

In April 1983, a massive landslide (specifically a complex earthflow) dammed the Spanish Fork River. The residents were evacuated as nearly 65,000 acre feet (80,000,000 m3) of water backed up, flooding the town. Thistle was destroyed; only a few structures were left partially standing. Federal and state government agencies have said this was the most costly landslide in United States history, the economic consequences of which affected the entire region. The landslide resulted in the first presidentially declared disaster area in Utah.U.S. Route 6 (US‑6), U.S. Route 89 (US‑89) and the railroad (now part of Union Pacific Railroad's Central Corridor) were closed for several months, until they were rebuilt on a higher alignment overlooking the area. The remains of Thistle are visible from a view area along US‑89 or from the California Zephyr passenger train.

Tortum Dam

Tortum Dam is a dam on the Tortum River in Erzurum Province, Turkey. The development, backed by the Turkish State Hydraulic Works, was built on a natural landslide near Tortum Waterfall and raises the level of the existing lake for hydroelectric power production.

Wila Lluxi

Wila Lluxi (Aymara wila blood, blood-red, lluxi shell of a mussel; landslide, "red shell" or "red landslide", Hispanicized spellings Wila Lloje, Huilaroje) is a mountain in the Andes, about 5,596 m (18,360 ft) high. It lies in the Cordillera Real of Bolivia in the La Paz Department, Los Andes Province, Batallas Municipality, Kirani Canton. It is situated on the western side of the Janq'u Quta valley next to the mountains Warawarani and Phaq'u Kiwuta. Other prominent mountains nearby are Janq'u Laya and Janq'u Uyu in the north, and Wila Lluxita and Mullu Apachita in the northeast, all of them higher than 5,000 m.

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