- ALASKA VOLCANO OBSERVATORY GLOSSARY
Rapidly moving, dry flows of disaggregated rock debris, sand, and silt. Volcanic debris avalanches commonly form by some type of structural collapse of the volcano, usually the steep front of the cooled lava dome, or other parts of the upper edifice. A large portion of the volcano may become unstable, break away from the volcanic massif, and become an avalanche. A debris avalanche may be triggered by an eruption or earthquake. Debris avalanches move at velocities ranging from a few tens of meters per second to more than 100 meters per second and behave like complex granular flows or slide flows. Commonly they are quite voluminous (greater than 10 cubic kilometers) and may run out considerable distances (up to 85 kilometers) from their source. The resulting debris-avalanche deposit usually exhibits hummocky surface morphology.\USGS PHOTO GLOSSARY OF VOLCANIC TERMSor volcanic landslideDebris avalanches are moving masses of rock, soil and snow that occur when the flank of a mountain or volcano collapses and slides downslope. As the moving debris rushes down a volcano and into river valleys, it incorporates water, snow, trees, bridges, buildings, and anything else in the way. Debris avalanches may travel several kilometers before coming to rest, or they may transform into more water-rich lahars, which travel many tens of kilometers downstream.\\Sketch and animation by B. MyersA debris avalanche rushes down the side of a volcano to the valley floor. Many such debris avalanches transform into lahars and travel tens of kilometers from the volcano. Note horseshoe shaped crater on volcano's side, which is the scar created by the avalanche.
Glossary of volcanic terms. - University of Wisconsin Oshkosh. G. J. Hudak. 2001.
Look at other dictionaries:
debris avalanche — The mass movement process, associated sediments (debris avalanche deposit), or resultant landform characterized by a very rapid to extremely rapid type of flow dominated by the sudden downslope movement of incoherent, unsorted mixtures of soil … Glossary of landform and geologic terms
debris-avalanche — “+| noun : a mass of rock fragments and soil that has moved rapidly down a steep mountain slope or hillside and because of its high water content has behaved like an avalanche of snow compare debris slide … Useful english dictionary
Avalanche — This article refers to the natural event. For other uses, see Avalanche (disambiguation) An avalanche is an abrupt and rapid flow of snow, often mixed with air and water, down a mountainside. Avalanches are among the biggest dangers in the… … Wikipedia
avalanche — ALASKA VOLCANO OBSERVATORY GLOSSARY A large mass of material or mixtures of material falling or sliding rapidly under the force of gravity. Avalanches often are classified by their content, such as snow, ice, soil, or rock avalanches. A mixture… … Glossary of volcanic terms
debris-slide — ˌslīd noun : a mass of predominantly unconsolidated and incoherent soil and rock fragments that has slid or rolled rapidly down a steep slope when comparatively dry to form an irregular hummocky deposit compare debris avalanche … Useful english dictionary
avalanche — [ avalɑ̃ʃ ] n. f. • 1611; lavanche XVIe; mot savoyard lavantse; bas lat. labina « glissement de terrain », de labi (cf. labile); altér. d apr. 1. aval 1 ♦ Masse de neige qui se détache d une montagne, qui dévale en entraînant des pierres, des… … Encyclopédie Universelle
Avalanche dam — Avalanche dams (anti avalanche dams, avalanche protection dams) are a type of avalanche control structures used for protection of inhabited areas, roads, electric lens, etc., from avalanches. The two major types are deflection and catchment dams … Wikipedia
Debris flow — Scars formed by debris flow in great Los Angeles during the winter of 1968 1969. The photograph was taken within several months of the debris flows occurring. A debris flow is a fast moving, liquefied landslide of unconsolidated, saturated debris … Wikipedia
avalanche — /av euh lanch , lahnch /, n., v., avalanched, avalanching. n. 1. a large mass of snow, ice, etc., detached from a mountain slope and sliding or falling suddenly downward. 2. anything like an avalanche in suddenness and overwhelming quantity: an… … Universalium
débris — nm. débri (Albanais 001, Saxel 002). E. : Amas, Dépôt, Grain, Poussière, Repas, Tas. A1) débris, morceau : bokon nm. (001, Villards Thônes 028) ; beurka nf. (Cordon) A2) des débris (de verre...) : du débri de vêro (002). A3) petit débris (de pain … Dictionnaire Français-Savoyard