Sink Holes

Sinkholes happen when there is water that gathers in a certain area because there is no drainage and it causes pits to form.

When water drains above or below ground, it can cause the area to dissolve and it can cause areas that are made of bedrock and other rocks to break.

Some rocks are more likely to break such as:

  • Gypsum
  • Bedrock
  • Limestone
  • Dolomite

When a hole begins to open and rock and asphalt begin to collapse and the hole gets bigger and bigger, this is a sinkhole.  This forms when there is nothing left under the ground to support the ground.


Types of Sinkholes

There are three major types of sinkholes:  solution sinkholes, cover collapse sinkholes, and cover subsidence sinkholes.

  • Solution sinkholes -These are the sinkholes that are the most seen sinkholes.  These happen on the surface and they happen mostly because of water that goes into the bedrock.  When a small hole starts to form, this is the start of the sinkhole.  After a sinkhole starts, it can expand quickly or take a lot of time.
  • Cover collapse sinkhole -The cover collapse sinkholes happen when bedrock under the soil gets eroded and begins to crack.  This causes the area to become weak.  Soon there will be a large hole underneath and the land above has no support.  This causes the ground above to collapse and can cause a large hole in just minutes.
  • Cover subsidence sinkhole -The cover subsidence sinkhole happens when the hole starts small and takes a long time before there is a big hole.  When the bedrock erodes, it causes cracks to form and this will eventually cause a hole.

How Do Sinkholes Happen?

  • Because of nature
  • Because of people

Sinkholes that happen because of nature happen because the ground begins to erode or because water underground builds up.

Most of the time, the sinkholes begin to happen a long time before we realize that they are being formed.

Since the ground is made of rocks, minerals, and dirt, water is all of the time moving in between the rocks and the dirt.  When this happens, the water is causing the rocks to break away.

When there is a lot of water that is under the ground, it starts to wash away the structure of the ground above it.  When the structure becomes thinner and weaker, it causes it to break and it causes a hole to form.

When new buildings or structures are built, they can change the way that the water in the Earth drains.

When this happens, it can cause the rock to get weaker and since the rock is supporting the ground, it begins to wear down and can eventually sink or fall in on itself.

How are MOST Sinkholes Made?

Most sinkholes happen because of erosion.  When rock and water are removed and when rocks begin to fall down, or when there are water main breaks and not enough groundwater, this can cause sinkholes.


What are Sinkholes Sometimes Called?

  • Sinkholes
  • Blackholes
  • Tiangkengs
  • Cenotes
  • Blue Holes
  • Sotanos
  • Tomo

What Type of Rock Causes More Sinkholes?

Limestone sinkhole – rainforest of Chiapas, Mexico,

There are different types of rocks but rocks that have bedrock, limestone, salt, and carbonate rocks are more likely to have sinkholes.

The rocks erode faster than other rocks and when this happens, the rocks can break away and this causes more sinkholes to form.

How Big are Sinkholes?

Sinkholes can be small or really big.  Some of them are so big that they are hundreds of miles long and super deep.

Sinkholes can be 3.3 feet to 2,000 feet in width and in-depth.

Where Are Sinkholes More Common?

Sinkhole in Sidewalk
  • Florida
  • Texas
  • Alabama
  • Tennessee
  • Pennsylvania
  • Missouri
  • Kentucky

Are Sinkholes Dangerous?

Sinkholes can be very dangerous if people get in them.  Sometimes, people do not know that sinkholes are forming, and they can form and can cause homes, cars and even people to fall into the sinkhole.

Other things that can happen from sinkholes are:

  • Cause chemicals to pollute groundwater.
  • Are dangerous to the foundations of homes and buildings.
  • It can mess up drains and sewer systems.
  • Cause property damage.

What Are Some Famous Sinkholes?

Guatemala City Sinkhole
  • In 2010 in Guatemala City, a sinkhole that was 65-foot-wide and 100 foot deep formed.  This sinkhole killed 15 people.
  • In 2014, at the Skydome area of the National Corvette Museum, a sinkhole that was 40-foot-wide and 20-foot-deep caused part of the floor to collapse.  Some of the Corvettes and other materials fell into the sinkhole.
  • The deepest sinkhole happened in Xiaozhai tiankeng in China.
  • In Belize, there is a sinkhole that is 124 meters deep and it is found in an atoll.
  • In Croatia, there is a sinkhole that is 530 meters.
  • In 2018, in Sydney, a sinkhole opened and caused an explosion and a tree to be knocked over.

In Mexico, a type of sinkhole happens where caves that are underground get filled with water and then they collapse.  These are sinkholes but they are called cenotes.  When these sinkholes come, the people are able to get fresh water from them and so these types of sinkholes are not as bad as other sinkholes.

Can a Sinkhole Be Stopped?

A sinkhole can be stopped if it is found in time.  If someone finds a sinkhole starting, they can put grout into the hole, and it can cause the sinkhole to be stopped.  This can help to save areas from a lot of damage.

Chinchón dolina

How Can You Tell if a Sinkhole is Forming?

There are some signs that a sinkhole could be developing under your home such as:

  • Fences that have sagging posts.
  • Windows that will not close right.
  • Doors that do not close right.
  • Water is collecting in part of the ground that it never collected before.
  • Trees that lean.

Sinkhole Facts for Kids:

  • The deepest sinkhole in the world is in Chongqing China.
  • In Florida, people have to have sinkhole insurance because sinkholes happen so much there.
  • Many areas in Australia have sinkholes.
  • Sotanos are sinkholes that are in Mexico.
  • A Tiankeng is a super large sinkhole that happens when a cave or cavern collapses.
  • Some of the largest sinkholes are found in Asia, Africa, the Caribbean, Europe, North America, South America, and Oceania.
  • A sinkhole in Winter Park, Florida is now a lake called Lake Rose.

What Did You Learn?

  • What is a sinkhole?  A sinkhole is when the Earth under the ground begins to erode and the surface is not held up and causes a hole to form.
  • What are the three types of sinkholes?  The three types of sinkholes are the solution sinkholes, cover collapse sinkholes, and cover subsidence sinkholes.
  • What causes sinkholes to form?  Sinkholes can be caused by nature or be caused by people.
  • Are sinkholes dangerous?  Sinkholes can be dangerous to people that fall into them and to the area around them.
  • Are some sinkholes useful? Some sinkholes are later used as lakes or to collect freshwater and can be seen as useful.