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Crevasse Fields Of Antarctica
A crevasse is a deep crack, that forms in a glacier or ice sheet that can be a few inches across to over 40 feet. Crevasses form as a result of the movement and resulting stress associated with the shear stress generated when two semi-rigid pieces above a plastic substrate have different rates of movement. The resulting intensity of the shear stress causes a breakage along the faces. Description Crevasses often have vertical or near-vertical walls, which can then melt and create seracs, arches, and other ice formations. These walls sometimes expose layers that represent the glacier's stratigraphy. Crevasse size often depends upon the amount of liquid water present in the glacier. A crevasse may be as deep as 45 metres and as wide as 20 metres. by |
Levee Breach
A levee breach or levee failure (the word dike or dyke can also be used instead of levee) is a situation where a levee fails or is intentionally breached, causing the previously contained water to flood the land behind the levee. Causes of failure Man-made levees can fail in a number of ways. The most frequent (and dangerous) form of levee failure is a ''breach''. A ''levee breach'' is when part of the levee actually breaks away, leaving a large opening for water to flood the land protected by the levee. Foundation failure A breach can be a sudden or gradual failure that is caused either by surface erosion or by a subsurface failure of the levee. Levee breaches are often accompanied by levee boils, or sand boils. The underseepage resurfaces on the landside, in the form of a volcano-like cone of sand. Boils signal a condition of incipient instability which may lead to erosion of the levee toe or foundation or result in sinking of the levee into the liquefied foundation below. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rope Team
The term rope team (german: Seilschaft), roped team or roped party, originally came from mountain sports, especially climbing, where it describes a group of people joined by a mountain or climbing rope and thus secured against falling. Mountaineering In mountain sports, especially climbing, a rope team is a group of mountaineers or climbers who are linked together by a safety rope. In a more general sense, a group of mountaineers, who are travelling together, may also be known as a rope team. The common safety rope helps to protect individual members of the group from falling. That said, it may also heighten the risk for the group as a whole because, in unfavourable conditions, the fall of a single member may pull the entire party down as well. In glacier crossings and on easier terrain, long stretches of the route may be negotiated purely by members of the climbing team being roped together without an anchor point being used. For this so-called "walking on a rope" everyone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mountaineering
Mountaineering or alpinism, is a set of outdoor activities that involves ascending tall mountains. Mountaineering-related activities include traditional outdoor climbing, skiing, and traversing via ferratas. Indoor climbing, sport climbing, and bouldering are also considered variants of mountaineering by some. Unlike most sports, mountaineering lacks widely applied formal rules, regulations, and governance; mountaineers adhere to a large variety of techniques and philosophies when climbing mountains. Numerous local alpine clubs support mountaineers by hosting resources and social activities. A federation of alpine clubs, the International Climbing and Mountaineering Federation (UIAA), is the International Olympic Committee-recognized world organization for mountaineering and climbing. The consequences of mountaineering on the natural environment can be seen in terms of individual components of the environment (land relief, soil, vegetation, fauna, and landscape) and location/z ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacial Landforms
Glacial landforms are landforms created by the action of glaciers. Most of today's glacial landforms were created by the movement of large ice sheets during the Quaternary glaciations. Some areas, like Fennoscandia and the southern Andes, have extensive occurrences of glacial landforms; other areas, such as the Sahara, display rare and very old fossil glacial landforms. Erosional landforms As the glaciers expand, due to their accumulating weight of snow and ice they crush and abrade and scour surfaces such as rocks and bedrock. The resulting erosional landforms include striations, cirques, glacial horns, arêtes, trim lines, U-shaped valleys, roches moutonnées, overdeepenings and hanging valleys. * Cirque: Starting location for mountain glaciers * Cirque stairway: a sequence of cirques * U-shaped, or trough, valley: U-shaped valleys are created by mountain glaciers. When filled with ocean water so as to create an inlet, these valleys are called fjords. * Arête: spiky high ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glaciology
Glaciology (; ) is the scientific study of glaciers, or more generally ice and natural phenomena that involve ice. Glaciology is an interdisciplinary Earth science that integrates geophysics, geology, physical geography, geomorphology, climatology, meteorology, hydrology, biology, and ecology. The impact of glaciers on people includes the fields of human geography and anthropology. The discoveries of water ice on the Moon, Mars, Europa and Pluto add an extraterrestrial component to the field, which is referred to as "astroglaciology". Overview A glacier is an extended mass of ice formed from snow falling and accumulating over a long period of time; glaciers move very slowly, either descending from high mountains, as in valley glaciers, or moving outward from centers of accumulation, as in continental glaciers. Areas of study within glaciology include glacial history and the reconstruction of past glaciation. A glaciologist is a person who studies glaciers. A glacial geologist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science (journal)
''Science'', also widely referred to as ''Science Magazine'', is the peer-reviewed academic journal of the American Association for the Advancement of Science (AAAS) and one of the world's top academic journals. It was first published in 1880, is currently circulated weekly and has a subscriber base of around 130,000. Because institutional subscriptions and online access serve a larger audience, its estimated readership is over 400,000 people. ''Science'' is based in Washington, D.C., United States, with a second office in Cambridge, UK. Contents The major focus of the journal is publishing important original scientific research and research reviews, but ''Science'' also publishes science-related news, opinions on science policy and other matters of interest to scientists and others who are concerned with the wide implications of science and technology. Unlike most scientific journals, which focus on a specific field, ''Science'' and its rival ''Nature (journal), Nature'' c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greenland Ice Sheet
The Greenland ice sheet ( da, Grønlands indlandsis, kl, Sermersuaq) is a vast body of ice covering , roughly near 80% of the surface of Greenland. It is sometimes referred to as an ice cap, or under the term ''inland ice'', or its Danish equivalent, ''indlandsis''. An acronym, GIS, is frequently used in the scientific literature. It is the second largest ice body in the world, after the Antarctic ice sheet. The ice sheet is almost long in a north–south direction, and its greatest width is at a latitude of 77°N, near its northern margin. The average thickness is about and over at its thickest point. In addition to the large ice sheet, smaller ice caps (such as Maniitsoq and Flade Isblink) as well as glaciers, cover between around the periphery. The Greenland ice sheet is adversely affected by climate change. It is more vulnerable to climate change than the Antarctic ice sheet because of its position in the Arctic, where it is subject to the regional amplification o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Freedom Of The Hills
''Mountaineering: The Freedom of the Hills'' is often considered the standard textbook for mountaineering and climbing in North America. The book was first published in 1960 by The Mountaineers of Seattle, Washington. The book was written by a team of over 40 experts in the field. The book grew out of the annual climbing course run since 1935 by the Mountaineers, for which the reading material was originally a combination of European works and lecturers' mimeo outlines. These were assembled into the ''Climber's Notebook'' and published by the Mountaineers as the hardbound ''Mountaineers Handbook'' in 1948. By 1955 the rapid postwar evolution of climbing techniques and tools had made the ''Handbook'' out of date, and the effort was begun to produce ''Freedom of the Hills''. Nearly 80 major contributors are credited in the first edition and were organized by a committee of 8 editors. The first four editions were only available in hardcover. Editions Chapter list In the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tensile Stress
In continuum mechanics, stress is a physical quantity. It is a quantity that describes the magnitude of forces that cause deformation. Stress is defined as ''force per unit area''. When an object is pulled apart by a force it will cause elongation which is also known as deformation, like the stretching of an elastic band, it is called tensile stress. But, when the forces result in the compression of an object, it is called compressive stress. It results when forces like tension or compression act on a body. The greater this force and the smaller the cross-sectional area of the body on which it acts, the greater the stress. Therefore, stress is measured in newton per square meter (N/m2) or pascal (Pa). Stress expresses the internal forces that neighbouring particles of a continuous material exert on each other, while strain is the measure of the deformation of the material. For example, when a solid vertical bar is supporting an overhead weight, each particle in the bar pushes o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Sheets
In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacial ice that covers surrounding terrain and is greater than . The only current ice sheets are in Antarctica and Greenland; during the Last Glacial Period at Last Glacial Maximum, the Laurentide Ice Sheet covered much of North America, the Weichselian ice sheet covered Northern Europe and the Patagonian Ice Sheet covered southern South America. Ice sheets are bigger than ice shelves or alpine glaciers. Masses of ice covering less than 50,000 km2 are termed an ice cap. An ice cap will typically feed a series of glaciers around its periphery. Although the surface is cold, the base of an ice sheet is generally warmer due to geothermal heat. In places, melting occurs and the melt-water lubricates the ice sheet so that it flows more rapidly. This process produces fast-flowing channels in the ice sheet — these are ice streams. The present-day polar ice sheets are relatively young in ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snow Bridge
Snow comprises individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water throughout its life cycle, starting when, under suitable conditions, the ice crystals form in the atmosphere, increase to millimeter size, precipitate and accumulate on surfaces, then metamorphose in place, and ultimately melt, slide or sublimate away. Snowstorms organize and develop by feeding on sources of atmospheric moisture and cold air. Snowflakes nucleate around particles in the atmosphere by attracting supercooled water droplets, which freeze in hexagonal-shaped crystals. Snowflakes take on a variety of shapes, basic among these are platelets, needles, columns and rime. As snow accumulates into a snowpack, it may blow into drifts. Over time, accumulated snow metamorphoses, by sintering, sublimation and freeze-thaw. Where the climate is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parque Estatal Chugach, Alaska, Estados Unidos, 2017-08-22, DD 94
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Parque is the Galician, Portuguese and Spanish word for "park", and may refer to: * Parque (TransMilenio), a metro station in Bogotá, Colombia * Parque (Lisbon Metro), in Portugal * Parque (Santurce), a subbarrio in San Juan, Puerto Rico * Jim Parque, a baseball player See also * Parquetry, a type of flooring * Park (other) A park is an area of land with a recreational or other specific purpose. Park or Parks may also refer to: Places United Kingdom * Park (Reading ward), an electoral ward of the Borough of Reading, Berkshire, England * Park (Sefton ward), an el ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
