Sinkhole
- Formation. It involves natural erosion or the gradual removal of poorly soluble bedrock (such as limestone) through infiltration of water, collapse of a cave roof, or lowering of the water ...
- Occurrence. ...
- Human Uses. ...
- Warning signs. ...
- Sinkhole Types. ...
- Some of the largest sinkholes in the world are. ...
- References. ...
What type of rock is most susceptible to sinkholes?
Soluble rocks include salt beds and domes, gypsum, and limestone and other carbonate rock. Florida, for instance, is an area largely underlain by limestone and is highly susceptible to sinkholes. When water from rainfall moves down through the soil, these types of rock begin to dissolve.
How do sinkholes affect the environment?
The sinkholes destroyed homes, roads and sections of cultivated areas. Credit: Ann Tihansky, USGS Sinkholes are common where the rock below the land surface is limestone, carbonate rock, salt beds, or rocks that can naturally be dissolved by groundwater circulating through them. As the rock dissolves, spaces and caverns develop underground.
What are sinkholes made of?
Sinkholes are most common in what geologists call, “karst terrain.” These are regions where the types of rock below the land surface can naturally be dissolved by groundwater circulating through them. Soluble rocks include salt beds and domes, gypsum, and limestone and other carbonate rock.
Where do sinkholes occur?
Sinkholes are most common in what geologists call, “karst terrain.” These are regions where the types of rock below the land surface can naturally be dissolved by groundwater circulating through them.
What type of erosion causes sinkholes?
Sinkholes are cavities in the ground that form when water erodes an underlying rock layer. Two types of sinkholes exist. One forms when the roof of a cave collapses and exposes the underground cavern. The second type forms when water dissolves the rock underneath soil and creates an underground chasm.
What kind of erosion produces sinkholes quizlet?
Landslides and mudslides happen when gravity pulls rocks, soil, or water downhill. Rocks and soil can slide downhill when they are loosened by water and the effects of weathering. Sinkholes occur when the rocks underground become porous and cannot support the ground above them, causing a hole to open up in the ground.
How are sinkholes formed erosion?
A sinkhole is a hole in the ground that forms when water dissolves surface rock. Often, this surface rock is limestone, which is easily eroded, or worn away, by the movement of water. In a landscape where limestone sits underneath the soil, water from rainfall collects in cracks in the stone.
What processes cause sinkholes?
When water from rainfall moves down through the soil, these types of rock begin to dissolve. This creates underground spaces and caverns. Sinkholes are dramatic because the land usually stays intact for a period of time until the underground spaces just get too big.
What causes most erosion?
Erosion by Water Liquid water is the major agent of erosion on Earth. Rain, rivers, floods, lakes, and the ocean carry away bits of soil and sand and slowly wash away the sediment.
What type of changes does erosion cause?
The movement of pieces of rock or soil to new locations is called erosion. Weathering and erosion can cause changes to the shape, size, and texture of different landforms (such as mountains, riverbeds, beaches, etc). Weathering and erosion can also play a role in landslides and the formation of new landforms.
Which two processes form most sinkholes?
The processes of dissolution, where surface rock that are soluble to weak acids, are dissolved, and suffusion, where cavities form below the land surface, are responsible for virtually all sinkholes in Florida. Dissolution of the limestone or dolomite is most intensive where the water first contacts the rock surface.
Are sinkholes erosion or deposition?
Over time, surface drainage, erosion, and deposition of sinkhole into a shallower bowl-shaped depression. Over time, surface drainage, erosion, and deposition of sediment transform the steep-walled sinkhole into a shallower bowl-shaped depression.
Where are sinkholes most likely to form?
Sinkholes have both natural and artificial causes. They tend to occur most often in places where water can dissolve the bedrock (especially limestone) below the surface, causing overlying rocks to collapse. Florida, Texas, Alabama, Missouri, Kentucky, Tennessee, and Pennsylvania are most sinkhole-prone.
What are the 3 types of sinkholes?
The Three Major Types Of SinkholesSolution sinkholes. Occur in areas where limestone is exposed at the surface or is covered by thin layers of soil or sand. ... Cover collapse sinkholes. ... Cover subsidence sinkholes.
In what rock do sinkholes occur?
Sinkhole appearance Some sinkholes result from the removal of a soluble rock such as chalk, gypsum or limestone. These are called solution sinkholes. These rocks dissolve when attacked by rainfall or groundwater that is acidic.
What do you think the cause of landslide or the type of sinkhole?
Our large rivers and hills also create many slopes and cliffs. When these can weaken, often due to heavy surface rains, they can fail, causing landslides or sinkholes. A landslide is a slipping of a slope or cliff that causes large amounts of rock and soil to collapse.
What are the two types of erosion described above quizlet?
there are 2 types of glacier erosion,plucking and abrasion. 1. plucking is the process in which a glacier flows over the land,picking up rocks and moving them. 2.
What processes are involved in erosion?
Erosion involved three processes: detachment (from the ground), transportation (via water or wind), and deposition.
What landforms are produced by gravity and erosion?
Mudflows and Lahars A mudflow is the sudden flow of mud down a slope because of gravity. Mudflows occur where the soil is mostly clay. Like landslides, mudflows usually occur when the soil is wet. Wet clay forms very slippery mud that slides easily.
Where does erosion most likely to occur in a meandering river quizlet?
Erosion occurs in the middle of the meander, whereas deposition occurs on the outside.
What causes sinkholes?
Sinkholes are caused by erosion. They may appear suddenly and have devastating consequences.
How are sinkholes created?
Manmade sinkholes are created when city development compromises the structural integrity of underlying rock. Roads, buildings, and other types of construction may cause water to collect in certain areas and wash away the supporting rock layer (especially at low sea levels and after a heavy rainfall).
Why are sinkholes natural?
Sinkholes have both natural and human causes. Land made of a soft underground rock layer, such as rock salt around the Dead Sea or limestone in Mexico’s Yucatan Peninsula, are often riddled with sinkholes, since the rock layer is easily dissolved. Manmade sinkholes are created when city development compromises the structural integrity ...
Where do sinkholes occur?
Most sinkholes occur in areas where the bedrock is formed from soft minerals and rocks like salt, gypsum, limestone, dolomite or others belonging to the evaporate or carbonate classes of rocks. Advertisement. Sinkholes typically develop slowly as bedrock is whittled away by water turned acidic from absorbing carbon dioxide ...
Why do sinkholes appear?
In some cases, sinkholes appear because of the combination of industrial activity or development, soft limestone bedrock and less than 200 feet (61 meters) of overburden [source: Southwest Florida Water Management District ]. The following human actions can also cause sinkholes: Drilling and vibrations. Mining.
Why does a sinkhole suddenly open?
In the case of the sinkhole suddenly opening to swallow a car that we just mentioned, it formed because the overburden was no longer stable enough to hold itself up. This common type of sinkhole is known as a collapse or cover-collapse sinkhole. Although these sinkholes can appear suddenly, the erosion that makes them happen has likely been taking place for weeks or years before, underground and out of view. So let's head underground.
What causes sinkholes in Florida?
In urban settings in particular, sinkholes may owe their development to human activity as much as anything else. In some cases, sinkholes appear because of the combination of industrial activity or development, soft limestone bedrock and less than 200 feet (61 meters) of overburden [source: Southwest Florida Water Management District ]. The following human actions can also cause sinkholes: 1 Drilling and vibrations 2 Mining 3 Changes in weight 4 Lots of foot or vehicle traffic 5 Heavy increase in water flow, formation of a pond or body of water, or broken pipes, among other things
How do sinkholes work?
With cover-subsidence sinkholes, water permeates the soft overburden. An example of this type of terrain is an overburden made up of up to 100 feet (30 meters) of sand with a small amount of clay below before yielding to soft limestone. As limestone dissolves and leaves a void, sediment from the overburden seeps in, creating a bowl-like impression in the Earth. These sinkholes, often only a few feet across and deep, are smaller than many others because after reaching a certain size, sand and sediment pour into the hole [source: Southwest Florida Water Management District ]. This inflow of sediment can block the outflow of water by stopping up the cracks and passages that connect the sinkhole to underground conduits. Many of these sinkholes then become ponds, as the water has nowhere to drain. They also don't produce the spectacular kind of cave-in associated with a cover-collapse sinkhole.
How deep are sinkholes?
Though many are less than 100 feet (30 meters) deep, sinkholes can look like ponds, cover hundreds of miles or fit discreetly in your backyard [source: USGS ]. Also called sinks, sinkholes owe much to water. A sinkhole usually forms by erosion caused by frequent exposure to water.
What is the identity of a sinkhole?
A sinkhole's identity centers on the gaps, crevices, cavities and voids that lie under the overburden, or the soil above the bedrock. As these gaps develop, expand and merge, soil from the overburden starts filling the void.
What are sinkholes associated with?
Sinkholes are associated with something missing from the Earth's surface. The hole visible on the ground has swallowed some material (also on the order of thousands of cubic meters), which was brought somewhere else. It is easy to understand the role played by sinkholes in legends and stories about the mystery of the underground, and the evil forces working below us. At the same time, literature works often mentioned sinkholes, or set their stories by using this feature, or other sinkhole-like landforms at the Earth's surface: we can recall here the Journey to the center of the Earth by Jules Verne (1864), and Alice Underground, the first version that was later on re-elaborated by Lewis Carroll (1865) to become the famous Alice's Adventures in Wonderland, just to provide a few examples. The film industry, too, was interested in using this karst landform in several occasions ( Fig. 2 ).
How dangerous are sinkholes?
Sinkhole. Sinkholes are particularly dangerous when they form instantaneously by collapse, and they often occur in significant numbers within a short time-span. From: Encyclopedia of Geology, 2005. Download as PDF.
Why are sinkholes important?
Apart from literature, history, and cinema, sinkholes are actually an important geological hazard in many parts of the world ( Waltham et al., 2005; Parise and Gunn, 2007 ), involving mostly karst terrains but also affecting many urban centers, due to presence of cavities excavated by man in different epochs below the towns (for anthropogenic sinkholes, see later on).
How does subsidence affect rock?
The progressive corrosional lowering of the rockhead may cause the gradual settlement of the overlying deposits by sagging, producing cover sagging sinkholes. These depressions are commonly shallow, have poorly defined edges, and may reach several hundred meters across. In the absence of subsurface data, they may be difficult to differentiate from cover and bedrock sagging sinkholes. Cover deposits may migrate downward into fissures and conduits by the action of a wide range of processes: downwashing of particles by percolating waters, cohesionless granular flows, viscous gravity flows, fall of particles, and sediment-laden water flows. The subsurface erosion of the cover material may produce two main types of sinkholes depending on the rheological behavior of the mantling deposits. Where the cover behaves as a ductile or loose granular material, it may settle gradually by suffosion processes, generating funnel- or bowl-shaped cover suffosion sinkholes, typically a few meters in diameter. When the cover behaves in a brittle way, upward migration of a cavity by successive failures eventually leads to the formation of a cover collapse sinkhole. These sinkholes are typically less than 15 m across, commonly appear in a sudden way, and have scarped or overhanging sides at the time of formation ( Figure 5 (a) ). Mass-wasting processes acting on their margins may cause their rapid enlargement and transform them into funnel- or bowl-shaped depressions. Cover collapse and cover suffosion sinkholes are generally the sinkhole types with the higher probability of occurrence ( Beck, 2005; Waltham et al., 2005; Gutiérrez et al., 2008b ). In a 10 km 2 sector of a terrace of the Ebro Valley (NE Spain) underlain by gypsum and intensively irrigated by sheet flooding, Gutiérrez et al. (2007) calculated a minimum probability of 44 cover collapse sinkholes/km 2 /year.
What landforms are forming episodically along subsurface structures?
Karst sinkholes are another landform that forms episodically along subsurface structures, and thus yields valuable data when trenched. These data include: (1) confirming or ruling out anomalies in the geophysical profiles (e.g., ground-penetrating radar) attributable to subsidence; (2) precisely locating the edge of some filled sinkholes; (3) obtaining information on subsidence mechanisms recorded by various deformation structures and cumulative subsidence magnitude; and (4) calculating minimum long-term subsidence rates using radiocarbon dates obtained from deformed sinkhole deposits. Trenching sinkholes to reconstruct their past behavior is in its infancy, but preliminary results are promising. For example, Gutierrez et al. (2009, 2011) have shown that the most-favorable sinkhole types for trenching are depressions generated by sagging and collapse mechanisms, with the greatest information occurring at sinkhole margins ( Figure 7 ). Once the trench has been logged, the log is retrodeformed in order to reconstruct the chronological sequence of deformation and sedimentary episodes.
What are sinkholes in karst?
Sinkholes are well defined depressions in the karst landscape, and can be ascribed within the most diagnostic features of karst. Produced by a variety of processes, from downward dissolution of soluble rocks, to stoping of a cave through upward roof migration, to internal erosion of soil in the overburden, sinkholes are difficult to predict.
What is the relevance of anthropogenic sinkholes?
(2008, 2014), the relevance of anthropogenic sinkholes will be pointed out, especially as regards the social and economic effects on the local communities and in terms of civil defense issues. Then, the focus will be on the inclusion of sinkhole as possible actor in a chain of hazards (multi-hazard event) and to their connection with other geological hazards such as earthquakes, floods and slope movements. With regard to these latter, the link with landslides will be particularly analyzed, being a research field worth of more detailed studies, and where not many efforts have been done so far in order to understand the possible connections between the hazards, and their chronological succession and evolution as well.
What is the process that causes sinkholes?
In the language of geologists, the process that causes sinkholes is "the creation of a void which migrates towards the surface". In the language of the layman, when there's not enough solid stuff left underneath to support what is left of the loose stuff above, the whole lot collapses.
What type of rock is a sinkhole?
Natural sinkholes – as opposed to manmade tunnel or cave collapses – occur when acidic rainwater seeps down through surface soil and sediment, eventually reaching a soluble bedrock such as sandstone, chalk, salt or gypsum, or (most commonly) a carbonate rock such as limestone beneath.
How deep is the sinkhole in Guatemala?
This sinkhole appeared overnight in a house in Guatemala City in 2011. It was 12.2m deep and 80cm in diameter. Photograph: Johan Ordonez/AFP
Where are sinkholes found?
Elsewhere in the US, sinkholes are common in Texas, Alabama, Missouri, Kentucky, Tennessee and Pennsylvania. In Britain, the BGS says the carboniferous limestone of the Mendip Hills, the north of the South Wales coalfield, the Peak District, the Yorkshire Dales, the northern Pennines and the edges of the Lake District all host well-developed karst ...
When did the sinkholes in Fontwell happen?
In chalky West Sussex in 1985, a burst water main caused an alarming rash of small 1m- to 4m-wide sinkholes to appear in Fontwell. "There was also a man who emptied his swimming pool out on to his garden, and was soon confronted with a large sinkhole under his house," Cooper says.
What causes a cave to collapse?
What finally triggers a collapse? The most common factor, Cooper says, is changing groundwater levels, or a sudden increase in surface water. During long periods of drought, groundwater levels will fall, meaning cavities that were once supported by the water they were filled with may become weaker (water pumping, for factories or farms, can have a similar effect). Conversely, a sudden heavy downfall can add dramatically to the weight of the surface layer of soil and clay, making it too heavy for the cave beneath to bear.
How to tell if you have a sinkhole?
At the most basic level, people in a sinkhole-prone zone are best advised simply to "look around them, at the adjacent land and buildings". Telltale signs may include sagging trees or fence posts, doors or windows that no longer close properly, and rainwater collecting in unlikely places.
