Types of Sinkholes and What Causes Them to Form
Types Of Sinkholes and What Causes Them To Form
In Florida, sinkholes don’t come as a surprise to residents. However, at times they can form without much warning causing great risk for those around it. When a sinkhole appears, it can be overwhelming and even more so to search for sinkhole repair services.
In order to properly assess a sinkhole, it is important you know there are 3 different types of sinkholes. They are as follows: Solution Sinkhole, Cover Collapse Sinkhole and Cover Subsidence Sinkhole.
1. Solution sinkholes are most commonly seen in areas that have a very thin cover of soil on the surface, exposing the bedrock below to continual erosion by water. As the water percolates through the bedrock, it carries away small parts of the rock with it. As the bedrock erodes, particles collect in the spaces it leaves. Over a period of time, a small depression is formed. It is at this point where the hole forms. The hole is usually bowl shaped and can be quite large. Sometimes the bedrock may suddenly collapse to form a solution sinkhole and other times it develops over time.
2. The second kind of sinkholes are known as Cover Collapse sinkhole. These take place when the bedrock is covered by a deep layer of soil and earth. Once the bedrock begins to get eroded, crack start forming in the rocky areas around it. When this happens, a number of weak points begin to form in the layers of soil and strata above it. Finally, it comes to a point when the weak points become a large hole within the bedrock that cannot support the weight above it. The cover collapse usually happens in a sudden manner and can create large holes in a matter of minutes.
3. The last kind of sinkholes are known as Cover Subsidence Sinkhole. In this case, the hole is formed over a period of time. The bedrock here is covered by soil and materials which are not well knitted together. Areas that have soil comprising largely of clay or sand often face the occurrence of this hole. Once the bedrock starts to erode, the clay or sand starts permeating through the cracks and settles into the spaces left behind. Over time, this creates a cavity on the surface of the soil and not under it.
As this happens, the water slowly erodes the rocks and minerals. Sometimes the flow of water increases to a point when it washes away the underground structure of the land. And when the structure becomes too weak to support the surface of the earth, it collapses and opens up a hole. This is how sinkholes are formed.
At times, humans are also responsible for the formation of sinkholes. Certain activities can result in small to large sinkholes.
Broken water or drain pipes
Improperly compacted soil after excavation work
Water from broken pipes can also penetrate through mud and rocks and erode the ground underneath, causing sinkholes. Sometimes, heavy weight on soft soil can result in collapse of ground, resulting in a sinkhole. Sinkholes can also form when the land surface is changed.
Areas that have a bedrock made of limestone, salt deposits or carbonate rock are most susceptible to erosion and the formation of such holes. These rocks tend to erode as acidic water passes through them. When rainwater passes through decaying plant debris, it tend to become more acidic. Over a period of years, overlying sediments collapse and a sinkhole develops. Sometimes the holes are small, measuring a few feet wide and ten to fifteen feet deep. Others can be hundreds of miles wide and deep. However, all of them can be dangerous for those that get caught in them.