What areas are at risk. What you can do to protect yourself. Where you can get additional information on landslide and mudflow hazards. Links with this icon indicate that you are leaving the CDC website.
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You will be subject to the destination website's privacy policy when you follow the link. CDC is not responsible for Section compliance accessibility on other federal or private website. Cancel Continue. There are two main types of erosion: chemical and physical. In physical erosion, the rock breaks down but its chemical composition remains the same, such as during a landslide or bioerosion, when plants take root and crack rocks. Explore the process of erosion with this collection of resources.
The environmental hazards you face depend on where you live. For example, if you live in northern California you are more likely to be impacted by a wildfire, landslide, or earthquake than if you live in Charleston, South Carolina, but less likely to be hit by a hurricane. This is because the physical conditions in each place are different.
The active San Andreas fault runs through California and causes regular earthquakes, while the warm waters transported by the Gulf Stream can intensify a storm heading for South Carolina. These environmental hazards shape human activity regionally. Learn more about environmental hazards with this curated resource collection. Weathering is the process of the weakening and breakdown of rocks, metals, and manmade objects. There are two main types of weathering: chemical and physical. An example of chemical weathering is acid rain.
Caused mostly by the burning of fossil fuels, acid rain is a form of precipitation with high levels of sulfuric acid, which can cause erosion in the materials in which it comes in contact. An example of physical weathering is wind blowing across the desert playas. This process causes rocks to form a specific pyramid-like shape and they are called ventifacts. Select from these resources to teach about the process of weathering in your classroom. During an avalanche, a mass of snow, rock, ice, soil, and other material slides swiftly down a mountainside.
An alluvial fan is a triangle-shaped deposit of gravel, sand, and smaller materials called alluvium. A pyroclastic flow is a dense, fast-moving flow of solidified lava pieces, volcanic ash, and hot gases. It is extremely dangerous to any living thing in its path. Join our community of educators and receive the latest information on National Geographic's resources for you and your students.
Skip to content. Twitter Facebook Pinterest Google Classroom. Encyclopedic Entry Vocabulary. A landslide is the movement of rock , earth , or debris down a slope d section of land. Landslides are caused by rain , earthquake s, volcano es, or other factors that make the slope unstable. Geologist s, scientists who study the physical formations of the Earth, sometimes describe landslides as one type of mass wasting.
Extreme rainfall temporarily drives the water pressure within a slope to a critical level; the stresses within the slope then exceed their stability point and the land begins to slip down the slope. Landslides are then driven simply by gravity, often assisted by a loss of strength in the region at the base of the slide.
So parts of the world with steep slopes, intense rainfall and large earthquakes tend to be most prone to this kind of geological disaster.
If engineers or builders mess up and make a slope too steep, it may no longer be held up by the intrinsic strength of the rock. In the same way, apparently simple things like leaky water pipes or inadequate drainage on man-made slopes can also start landslides.
This is particularly so water is either retained in, or drains particularly slowly from, the rock or soil of the slope. Certain kinds of clays are particularly notable for these features — and this seems to have exacerbated the landslides at Hiroshima. Such conditions are generally well understood by geo-technical engineers, so can normally be predicted in artificial slopes. Next time you are on a train or car look out for adjacent slopes which have lines of gravel or rock-fill running down them to drain the water away.
Tsunamis can be generated on Under what circumstances do U. Geological Survey landslide personnel conduct field work in landslide-prone areas? USGS landslide researchers have ongoing field projects in several areas of the United States, including parts of the Pacific coastal ranges, Rocky Mountains, and the Appalachians. USGS scientists also respond to major landslide events, including some that result in federally-declared disasters. In some cases, USGS scientists respond to landslides Can major landslides and debris flows happen in all areas of the U.
Landslides can and do occur in every state and territory of the U. What was the largest landslide in the United States? In the world?
The largest subaerial on land landslide in Earth's recorded history was connected with the eruption of Mount St. Helens volcano in Washington state, USA. That landslide had a volume of 2. What is the difference between a landslide advisory, a landslide watch, and a landslide warning? An advisory is a general statement about the potential of landslide activity in a given region relative to developing rainfall predictions.
An advisory may include general statements about rainfall conditions that can lead to debris-flow activity, and list precautions to be taken in the event of heavy rainfall. A watch means that landslide How many deaths result from landslides each year? An average of people are killed by landslides each year in the United States.
The worldwide death toll per year due to landslides is in the thousands. Most landslide fatalities are from rock falls, debris flows, or volcanic debris flows called lahars.
Twenty-three people were killed, at least injured, and more than homes were Do human activities cause landslides?
Yes, in some cases human activities can be a contributing factor in causing landslides. Many human-caused landslides can be avoided or mitigated.
They are commonly a result of building roads and structures without adequate grading of slopes, poorly planned alteration of drainage patterns, and disturbing old landslides. Detailed on-site Why study landslides? Landslides are a serious geologic hazard common to almost every State in the United States. As people move into new areas of hilly or mountainous terrain, it is important to understand the nature of their potential exposure to landslide hazards, and how cities, towns, and counties can plan for land-use, engineering of new construction and Filter Total Items: Year Published: Lahar—River of volcanic mud and debris Lahar, an Indonesian word for volcanic mudflow, is a mixture of water, mud, and volcanic rock flowing swiftly along a channel draining a volcano.
Major, Jon J. View Citation. Major, J. Geological Survey Fact Sheet —, 6 p. Lukas, Vicki; Carswell, Jr. Lukas, Vicki, and Carswell, W. Geological Survey Fact Sheet —, 2 p.
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