Friction and Dynamics of Rock Avalanches Travelling on Glaciers
Rationale
The study of rock avalanches travelling on glaciers or glaciated areas has centred around interpreting data collected from case studies throughout history. Looking at this data can confirm that, in general, rock avalanches travelling on glaciers have a reduced coefficient of friction compared to rock on rock avalanches. The decreased resistance contributes to a higher velocity and further distance travelled. The precise reason for this behaviour is the subject of the research paper; it explains how and why the dynamics of rock avalanches on glaciers are different and creates a model that describes the specific contact between a rock landslide and a glacier.
Research into the friction and dynamics of rocks collapsing onto glaciers is particularly interesting at a point in time where rising global temperatures are melting glaciated areas and affecting the frequency of rock landslides. In addition, younger mountain ranges are more prone to earthquakes, as well as being bigger. (have a tendency to be higher, and subject to more seismic and tectonic activity, meaning that) research into the mechanics(dynamics) of rock landslides on glaciers is particularly apt. The aim of the research paper is to create a new model that effectively examines the mechanics and dynamics of rock avalanches on glacial surfaces. The difference between this research and previous work done in the same area, is that this model aims to account for the layer of melted ice between the two surfaces that is formed during landslides, and to identify a relationship between the coefficient of friction, the speed, and distance travelled.
Method
The initial part of the resea...
... middle of paper ...
... in multiple areas. Although not the main aim of the research, the findings could easily be used to estimate risk and severity of landslides in glaciated areas. A future direction for this research also points to extraterrestrial investigation, especially where satellite images can indicate certain characteristics of apparent landslides on Mars. The research could help to confirm or deny the possibility that ice may have once existed on Mars.
In terms of future work relating to friction specifically, it is mentioned there is the possibility of a fine layer of mud would result from the movement along the glacier. Mud would have a more viscous properties than the present ice/water combination, and might require further investigation. The present model also doesn’t consider the friction that occurs as a result of rocks hitting one another or breaking apart.
University of Colorado, Boulder, August 11, 2003, NASA funds Colorado University at Boulder study of changes in Earth’s glacier systems in Ascribe Science News Service: pNa, p 1.
Firstly, the landscape around would be dramatically eroded. Whereas a glacier pushes out of the way objects in its path, and erodes the surrounding area through a combination of ablation, plucking and freeze-thaw, the glacier itself commonly hides the features it creates, but when the glacier melts, features such as cirques, horns, arêtes, hanging valleys and waterfalls can be seen. Also, the melt water would itself cut a small v-shape in the base of the U-shaped valley created by the glacier. The stones in the river, and deposition would cause this. Lateral and terminal moraines would also be created after the glacier deposits some of the rocks and dirt that it will have picked up as it moves.
Hoffman, Paul F.; Schrag, Daniel P. "Snowball Earth" Scientific America 21 Jan 2000 Scientific American Online. Online 31 Mar 2003
Glacier melting has become very rapid in the European Alps since 1980, and 10 to 20% of the ice in the Alps was gone in less than two years. Half the amount of Europe's Alpine glaciers has vanished since 1850. Within the next hundred years, 50 % of those left, will as
Often, the effects of Mountain top Removal are disastrous, the wildlife habitat is damaged and vegetation loss usually leads to numerous floods and landslides. When explosives are used, fly rock, ...
The term snow is usually restricted to material that fall during precipitation in the form of small white ice crystals formed directly from the water vapour of the air at a temperature of less than 0°C and has not changed much since it fell. A fall of snow on a glacier surface is the first step in the formation of glacier ice, a process that is often long and complex (Cuffey and Paterson, 2010). The transformation of snow to ice occurs in the top layers of the glaciers and the time of the transformation depends mostly on the temperature. Snow develops into ice much more rapidly on Temperate glaciers, where periods of melting alternate with periods when wet snow refreezes, than in Polar glaciers, where the temperature remains well below the freezing point throughout the year. The density of new snow as it falls on glacier surface depends mostly on the weather conditions. In clam conditions, the density of new snow is ρs ≈ 50 – 70 kg m-3 (Table 1.1). If it is windy, there is breaking of the corners of snowflakes, and the density is more like ρs ≈ 100 kg m-3. After the snow has fallen on the surface, there are three processes that are all active together and work to transform the snow to ice.
One of the most striking features in Glacier National Park is the color banding. This feature can be seen in nearly every mountain within the park as they are composed of different layers of rocks and colors. The rock strata are mainly composed of sedimentary rocks limestones, shales, sandstones, and lightly metamorphosed rocks (Dyson,1957). These rocks all belong to a single large unit known as the Belt series. The rocks are very unusual in that they were deposited in late in the Precambrian between 1600 and 800 million years ago and are relatively undeformed and only lightly metamorphosed (Alt, 1983). The rocks can be spotted throughout the large area of western Montana, northern Idaho, and southern British Columbia. The formation of the Belt Supergroup started during the Proterozoic era as a long narrow section of North America extending from the Arctic Ocean southward which slowly sank to form a large sea-filled trough also known as a geosyncline (Dyson, 1957). Streams from nearby lands carried muds and sands into the sea almost completely filling it. These muds were eventually compressed into shales, some limestones, and sands into sandstones. Many of the rocks in this series have very distinct features that give a clue about their origin, features suc...
"Snow Storms: What's a Blizzard." Forces of Nature: TQ 2000. Web. 3 Mar. 2014. .
The rocks that are round shape are the ones that move the most, and I could tell that most of the rocks when getting closer to campsite where round rocks, and that would probably mean that the glacier was dragging the rocks towards the bottom, since they are easier to move around. Some of the bedrock rocks had striations, it’s where a glacier moves across the underlying rocks and the process of abrasion wears it away the fragments of the rock held in the ice and it scraps the rock on the
Since the end of the last century, nearly global glaciers recession have been noticed (Barry, 2006). For example in Himalaya, several studies indicate receding glaciers in recent years and also these alpine glaciers are melting away remarkably quickly at the moment (Kodata et al, 2000; Fujita et al, 2001; Ren et al, 2006). Several researches show that during the past 25 years, these glaciers experienced a dramatic decline. These analyses reveals 22% glacier area loss in entire Alps, between 1985 and 1999, which is about seven times faster than for the 1985-1973 periods (Petri and Gareth, 2010). However, these result does not imply a synchronous behavior of all glacier around the world, because there can be local differences between glaciers and even in some glaciers advances. So, if the glaciers disappear, people distant from these mountains, in the lowlands and big cities of Asia and South American will suffer from ...
To begin with, the landing of the snow on the road caused many damages to them. This was because the levels on which the roads were raised were in different proportions. This, therefore, prevented lack of flow to be experienced on the roads. Moreover, the cracks that were observed on the roads came about because of the difference in the temperatures of the country.
...strous. These landslides were caused by the heavy rainfall which often caused the hills being dug to give way, resulting in massive landslides. The workers cut their way through the continent with dynamite and steam shovels. These engineering maneuvers were slow and time consuming but were completed successfully (McCullough 106-108).
There are many different glacial landforms created by glacial erosion, one of these landforms is U-shaped valleys or glacial troughs. This glacial landform has many distinct characteristics. One of these characteristics is that it has very steep valley sides caused by the glacier as it moves down the valley eroding the sides of the valley by the processes of abrasion and plucking. Abrasion is when the boulders and moraine carried by the glacier rubs and erodes the valley side as it physically moves down the valley. Plucking happens when the water in the glacier freezes inside of the cracks in the individual rocks on the valley side then the water freezes and as the glacier moves the rock is plucked or torn from the valley side producing the steep side to the valley.
U.S. Geological Survey. Worldwide Overview of Large Landslides of the 20th and 21st Centuries. 6 December 2010. 3 February 2011 .