Karst, kentucky geological survey, university of kentucky
A geologic hazard is a naturally occurring geologic condition that may result in property damage or may be a threat to the safety of people. Blogger webmaster tools The geologic hazards associated with karst are: sinkhole flooding, groundwater vulnerability, radon, and cover-collapse sinkholes described on this page. Webmaster tools with your google account What Is a Cover-Collapse Sinkhole?
Cover-collapse sinkholes occur in the soil or other loose material overlying soluble bedrock. How does webmaster tools work A sinkhole is any naturally occurring depression in the surface of the ground from which rainfall is drained internally.
Oogle webmaster tools Sinkholes that suddently appear form in two ways. Add webmaster tools In the first way, the bedrock roof of a cave becomes too thin to support the weight of the bedrock and the soil material above it. What are webmaster tools The cave roof then collapses, forming a bedrock-collapse sinkhole. Webmaster tools firefox Bedrock collapse is rare and the least likely way a sinkhole can form, although it is commonly incorrectly assumed to be the way all sinkholes form. Webmaster tools redirect The second way sinkholes can form is much more common and much less dramatic. Webmaster tools submit to index The sinkhole begins to form when a fracture in the limestone bedrock is enlarged by water dissolving the limestone. Webmaster tools home page click verify this site As the bedrock is dissolved and carried away underground, the soil gently slumps or erodes into the developing sinkhole. Webmaster tools home page dashboard Once the underlying conduits become large enough, insoluble soil and rock particles are carried away too. Webmaster tools crawl errors Dissolution sinkholes form over long periods of time, with occasional episodes of more rapid subsidence or collapse. Webmaster tools search queries no data available It is the collapse of the loose cover over the bedrock or soil that causes the problem. Google analytics vs google webmaster tools Sometimes the collapse will occur in an area with no indication of previous subsidence. Webmaster tools api In other words, a new sinkhole has formed. Webmaster tools com Sometime there was a preexisting sinkhole, but it had been filled in and covered over during land clearing or construction. Webmaster tools links to your site Factories or homes built over filled sinkholes may be damaged as the fill continues to be transported out of the sinkhole and cover collapse reoccurs. Webmaster tools data Why Does Cover Collapse Occur?
Many important aquifers are composed of granular materials such as sand and gravel or weakly cemented bedrock. Webmaster tools code Such aquifers occur in Kentucky, particularly along the Ohio River and in the Jackson Purchase Region. Free forex webmaster tools Groundwater flow in these aquifers is through the pores between the grains of sand or gravel or through narrow fractures in solid bedrock. Install webmaster tools Small openings act as a filter, physically or chemically removing most suspended matter, which holds back the soil cover. Webmaster tools in google analytics Water movement through the fracture system of a fractured bedrock aquifer or the pore spaces of a granular aquifer is slow, when compared to movement in a karst aquifer. Google webmaster tools free download The flow velocity in a granular aquifer is too slow, and the pores too small, to transport grains of soil.
The drainage patterns of karst conduits resemble the branching pattern formed by streams flowing above ground across insoluble rocks. Webmaster tools help center Water recharge to karst aquifers occurs either directly, through swallow holes and sinkholes, or indirectly, through the pores in the soil overlying the limestone bedrock. Webmaster tools guidelines The conduit of a karst aquifer is somewhat like a roofed creek bed and responds to rainfall like a storm sewer. Google analytics and webmaster tools Water flow is fast and turbulent, and significant amounts of sediment can be carried through the relatively large conduits. Webmaster tools crawl url As water flows through the soil into the underlying bedrock, it enlarges joints (cracks) in the bedrock to form grikes . Webmaster tools verification The grikes drain into small conduits, which in turn drain to a conduit large enough to be called a cave, which discharges to a spring . Online webmaster tools When the overlying soil is repeatedly wetted and dried, small amounts of soil are dislodged and carried away by the cave conduit draining the sinkhole. What is webmaster tools in seo Gradually, a void develops in the soil overlying the enlarged grike or conduit. Good webmaster tools The collapse occurs only in the overlying soil cover, not in the limestone bedrock. Webmaster tools keyword research Below is a diagram of the steps in the formation of a typical cover-collapse sinkhole.
Schematic diagram illustrating the development of a cover-collapse sinkhole. Googe webmaster tools Upper left, the soil arch develops; upper right, the arch begins to fail; lower left, the arch has collapsed and soil has been transported underground; lower right, the walls of the collapse slump and the depression takes on the classical bowl shape of the sinkhole until the next collapse.
Cover-collapse sinkholes can vary in size from 1 or 2 feet deep and wide, to tens of feet deep and wide. How to use webmaster tools Unlike large collapses, like those in Florida where the cover over the limestone is very thick, cover-collapse sinkholes in Kentucky are unlikely to swallow entire houses or businesses. Webmaster tools verification meta tag Cover-collapse sinkholes in Kentucky do severely damage buildings, drain farm ponds, damage roads, and wreck farming equipment. Free webmaster tools scripts The thickness and cohesiveness of the soil cover determine the size of a cover-collapse sinkhole. Website webmaster tools In Kentucky the thickness of soil, sand or clay, and bedrock fragments over limestone bedrock is typically less than 25 feet, so cover-collapse sinkholes more than 20 feet in diameter are uncommon. Outils webmaster en ligne Some precautions can be taken, however. List of webmaster tools How Can Cover-Collapse Sinkholes Be Avoided?
The only guaranteed method of avoiding karst geologic hazards is to avoid living on karst. Webmaster tools website But because such a large percentage of Kentucky is karst, that is clearly impractical for most people. Webmaster tools submit url The most effective way to avoid cover collapse sinkhole damage is to avoid buying or building a structure on a sinkhole that has been filled. Webmaster tools google seo Ask the seller if any sinkholes have been filled, and, if so, where, how, and by whom. Webmaster tools home page Look for previous damage to foundations and check doorframes and windows for squareness. Search engine webmaster tools Check the surrounding lot for shallow depressions and arch-shaped cracks in the soil. Webmaster tools backlinks Should a cover collapse occur on your property, it is possible to repair the damage. Webmaster tools optimization Repairing a Cover-Collapse Sinkhole
If a cover-collapse sinkhole develops under a building, the foundation of the building should be shored up as quickly as possible to avoid major foundation damage. What is google webmaster tools used for Several engineering techniques are available to transfer the load of the building to competent bedrock. Webmaster tools training The sinkhole can then be filled at a less urgent pace using a graded-filter technique (Reitz and Eskridge, 1977, Sowers, 1996), the foundation reinforced, and the soil graded. How to install webmaster tools The purpose of the graded filter is to allow water to seep into the ground while the soil is held back. Webmaster tools home page optimization In the case of farm ponds and lagoons, the graded filter construction is essentially the same, but the final layers are fine gravel, coarse sand, and fine sand. Webmaster tools malware The uppermost layer is bentonite clay or volclay, which blocks water seepage. Search webmaster tools help Always consult a professional geologist who is experienced in identifying karst subsidence and an engineer experienced in sinkhole remediation when dealing with any structure threatened by a cover-collapse sinkhole. Webmaster tools forum Reporting A Cover-Collapse Sinkhole
• Reitz, H.M., and Eskridge, D.S., 1977, Construction methods which recognize the mechanics of sinkhole development, in Dilamarter, R.R., and Csallany, S.C., eds., Hydrologic problems in karst regions: Bowling Green, Western Kentucky University, Department of Geology and Geography, p. Webmaster tools 2013 432-438.