Every once in a while, you’ll see a news story about a sinkhole that suddenly opens up and causes quite a stir. Although it may seem like these are rare oddities, sinkholes are actually quite common all over the world.

Sinkholes go by many names around the world, including “sinks,” “shake holes,” “swallow holes,” “swallets,” “dolines” and “cenotes.” Although they may be called by different names, they have similar causes.

Sinkholes are depressions or holes in the Earth’s surface caused by natural karst processes. Karst processes occur when water and chemicals dissolve carbonate rocks, such as limestone, to form sinkholes and caves.

For example, one common scenario involves the gradual erosion of bedrock by ground water that percolates down through cracks in the bedrock. As the rock erodes and weakens, spaces and caverns develop underground.

The land above the developing spaces usually remains intact until the rock underneath can no longer support it. When the underground spaces grow large enough, a sudden collapse of the surface land above can occur.

This is what happens when a sinkhole “suddenly” opens up. Of course, the underlying processes have been going on for some time.

Sinkholes can also be caused by human factors. For example, man-made mines that are no longer used occasionally cause collapses. Water and sewer pipes that break can also sometimes lead to the formation of sinkholes if they create underground flows that speed the process of erosion.

Sinkholes range in size from 3 feet to more than 2,000 feet — both in width and depth. The largest known sinkhole in the world is in China. Called the Xiaozhai tiankeng, it is almost 2,200 feet deep!

Sinkholes that form in coral reefs or islands can often be very deep and filled with water. They’re known as “blue holes” because of the deep blue color of the water in these holes. Blue holes often become popular spots for divers to explore.

Not all holes that suddenly open up in the ground are sinkholes, though. In May 2010, a huge hole opened up suddenly in Guatemala City, swallowing a three-story building and a house. Although news reports called this hole a “sinkhole,” it was actually something scientists call a “piping pseudokarst.”

Because there is no carbonate rock under Guatemala City, the hole couldn’t be caused by karst processes and thus technically couldn’t be defined as a sinkhole. Instead, the hole was caused by the collapse of large cavities that had developed over time in the thick volcanic ash deposits that exist under Guatemala City.


19 Join the Discussion

1 Star2 Stars3 Stars4 Stars5 Stars  (19 votes, avg. 4.37 out of 5)
  1. I think that is terrible! That building and all those cars and all of the people that could of got hurt or did. A sinkhole is a hole in the street and if your car tire gets stuck in it, you could get in an accident. I would rate the wonder of the day 4 stars. I love you wonderopolis!

    Oh and a shout out to the people that got hurt or almost did. Bless you all!

    • What a super nice thing to say, Paige! We appreciate your concern for the people affected by sinkholes. You have a big, WONDERful heart! :-)

    • That’s a really good guess, Vikkie! We WONDER if you are right? We’ll all get to find out when we visit tomorrow’s Wonder of the Day®! :-)

    • Thank you for exploring this Wonder of the Day® and for letting us know that you did some extra WONDERing about one of the sinkholes you learned of, Wonder Friend! :-)

    • We’re super sorry you seem to be having trouble viewing the video for this Wonder of the Day®, Phoenix! We’re not sure why your computer is telling you there’s a problem with Adobe Flash Player, because none of the content we’ve included in this Wonder uses Flash. Sometimes, schools and school districts place “blocks” on the videos on websites that are used by their students. It is their way of protecting you from the possibility of seeing something that’s not safe. It sounds like this is what might be happening for you today. Can you check with your teacher or computer lab teacher to see if he or she can help you? We appreciate you visiting Wonderopolis and hope you will be able to see the Wonder videos soon! :-)

  2. Cool website! I agree with Phoenix, my class and I are using this website for Science class, and we were suppose to watch the video. :(
    Overall, great website! I will be using this website more often. Even my principal uses it! :)

    Wonder Student

    • Hey there, Wonder Student, we’re super sorry to learn that our Wonder video isn’t working! We’re in the process of fixing it, but we really appreciate your comment! :)

      Please pardon our technology hiccup… and thanks for being an awesome Wonder Friend! We’re so excited that you’re part of a WONDERing school! :)

  3. Thanks Wonderopolis! You guys are awesome!
    I’m recommending this website to all my WONDERfriends! :)

    Reply soon!

    Wonder Student

    • Hey Wonder Student, we are so excited that you’ve been WONDERing with us today! It’s awesome to know that you enjoy spending time at Wonderopolis- we Wonder what your favorite topic is when it comes to WONDERing? Science, sports, art, reading? So many options to choose from- how WONDERful! :)

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