What Causes Sinkholes? Our Ultimate Prepper Guide
I’m going to be honest, if you came here looking for ways to survive a sinkhole, or get some prep for a sinkhole, you are going to be sorely disappointed. The following article is a guide to understanding exactly what sinkholes are, how they seem to form, and what regions of the world are prone to them. We will also discuss famous sinkholes and check out some sinkhole videos.
Sinkholes, as bad fortune would have it, are as mysterious now as they’ve ever been. Science is making efforts and advancements in sinkhole research, but the fact is, most sinkholes happen when and where people don’t typically expect them to happen. Yes, some places in the world are more prone to sinkholes, that however doesn’t shave much off the surprise when someone’s home, and sometimes residents collapse into the earth’s abyss with zero warning.
Sinkholes are as terrifying as they are misunderstood.
What is a Sinkhole?
In simple terms, a sinkhole is a hole that suddenly opens up in the earth. Sinkholes are infamous for swallowing homes, causing massive roadway closures, and being generally unpredictable. Sometimes sinkhole new stories are passed over, amounting to little more than a traffic alert. But sinkholes are a gateway into the earth’s crust, a door that opens us up to the abyss, and sometimes they create mystical and life-threatening cavities.
Although sinkhole potential is under a great many residents worldwide, they get very little media coverage unless they detrimentally affect life, limb, or luxurious product (more on that below). Earthquakes, which are not related to sinkholes, tend to get coverage even when they happen in the middle of nowhere and affect no human life or property. Sinkholes don’t tend to draw a crowd, but that’s likely because they aren’t greatly understood in a sophisticated way.
How do Sinkholes Form?
Sinkholes tend to form gradually, over time, as erosion within the earth’s soil occurs. The U.S. Geological Survey says that sinkholes form in areas that lack the ability to seamlessly handle water irrigation. The water that compiles eventually protrudes the earth’s soil and bedrock, causing it to tear away lining. Large caves often form below the earth’s surface, caves that are undetectable, sometimes with the weight of homes on top of them.
Sometimes a sinkhole will form in a way that is obvious. In those cases, residents in the area are given evacuation orders. Other times, a worse scenario plays out whereas a sinkhole erupts with no prior warning. There is hardly any rhyme or reason to either scenario.
This all really comes down to the water’s interaction with the ground. The erosion tears at the very fibers which lend support to the ground, and structures, and people, above it. Water moving around the internal grounds of the earth is eroding away that support system. Eventually, gravity and density win out and the earth opens up.
So what contributes to increased sinkhole potential?
- Faster moving water. If water is the great shredder of the earth’s support system, it would stand to reason faster-moving moving water would erode at a more furious rate.
- The earth’s composition. If the water is encountering larger stones and rocks, the earth may be able to fight the water’s pressure or resist it, for a longer period of time (potentially forever). Silk and clay, however, are composed mostly of smaller particles, creating an easy environment for our friend, water, to churn away at the support system. Some substances can erode through dissolving. Salt, for example, will dissolve when exposed to water over a lengthy amount of time.
- The earth’s ground is confined in space. Because the ground can’t run away, it is forced to adjust to the penetrating water. This adjustment means compensation for gravity. And that can mean the formation of an underground cavern and eventual collapse.
- Limestone bedrock as the core ground support. Limestone bedrock is incredibly soluble, making it the perfect partner in crime for water erosion.
Consider a concept for a moment: You’ve clearly seen erosion from water in topical examples. You’ve seen creeks, or small irrigation trails from where water has been funneled off the roof of a home down a yard’s hill, or areas on the sides of mountains which have eroded. That’s the same working concept that happens under the earth. We call this concept internal erosion.
Once the water penetrates the earth at a specified rate of speed and meets ripe conditions to erode the internal ground, the process is often a slow breakdown in support. Often, there are no real indicators that it is happening at all, which is why sinkholes are one of the earth’s most terrifying surprises.
Here’s a working example of how a sinkhole forms taken from the video above. You can see that the concept is rather simple in the way that water penetrates the earth and then wreaks havoc on carbonate bedrocks, such as limestone.
Not every sinkhole makes national news. The fact that sinkholes are largely misunderstood lessens their overall appeal to the masses. However, when sinkholes strike and cause injury, death, extreme property damage, or all of the above, they tend to get widespread coverage.
There are a number of famous sinkholes.
Corvette Museum Sinkhole
When the video from the National Corvette Museum’s security footage made national news, people were both stunned and bewildered. The video shows expensive, treasured Corvettes being suddenly swallowed up by the earth. At first watch, the video appears to be fabricated. Beyond that, it seems as though an earthquake potentially opens up at its fault line. However, this is Kentucky, a region not prone to largescale earthquake.
A sinkhole is determined to be the cause of the terrifying opening in the earth. Fortunately, the sinkhole opened up after hours, likely saving lives.
Oddly, the museum never fixed the damage. Instead, they pulled the cars, many of which suffered total damage, from the sinkhole and put them on display next to the sinkhole. According their PR, business has never been better. People often come by just to see the sinkhole and check out the cars that somewhat survived the incident. One of the cars showed little damage and started right after it was pulled from the abyss.
Florida Sinkhole Swallows House
One of the saddest sinkhole travesties to make headlines was in Florida, a place many call “sinkhole alley.” We will have much more on Florida below. This Florida sinkhole swallowed a man, causing sinkholes to suddenly get a lot more attention from the general public. Jeff Bush was swallowed up by a sinkhole. The sinkhole opened up suddenly beneath his bedroom. His body was never found.
“I ran toward my brother’s bedroom because I heard my brother scream,” Jeremy Bush told CNN’s “AC360.”
“Everything was gone. My brother’s bed, my brother’s dresser, my brother’s TV. My brother was gone.”
Taylor Yarkosky, known as “the sinkhole guy,” discussed the tragedy on Fox News shortly after it happened.
The national story involving Bush’s terrible fall to death put a terrifying new label on sinkholes. More and more people began to fear sinkholes, often calling around to find engineering businesses that could potentially survey their land for sinkhole potential.
The Guatemala Sinkhole
One of the most famous sinkholes in history happened in Guatemala on an urban street corner.
The Guatemalan sinkhole is a stunning 300 feet deep and 60 feet wide. In terms of known sinkholes, this one is as majestic as it is terrifying. Being located right in the center of an urban area makes it even more of a spectacle.
The Guatemala sinkhole is a bit of a contentious issue among scientists. First, it is caused by humans due to the influx of water being derived from a broken water pipe. Remember, a large part of the sinkhole formula is water, it doesn’t have to be rain water. The second contributor to the sinkhole is the fact that the predominant initial layers of earth in this area are the result of past volcanic activity, pumice fill. Pumice fill plus churning water amounts to sinkhole heaven.
The Guatemala sinkhole also proves that limestone isn’t the only type of earth that can allow for a sinkhole to form.
The New Zealand Sinkhole
In 2018, a farmer in the town of Rotorua, New Zealand discovered a massive sinkhole. His farm, built on degrading limestone bedrock, is commonly the sight of sinkholes. However, the size and scale of the 2018 New Zealand sinkhole was something more out of this world and size and scale.
Fencing was placed around the six story deep sinkhole to protect farm animals. The sinkhole stretches the length of two football fields. When you take into account the perspective of the man standing afar, you can get a much better idea of just how vast and large this sinkhole really is. This is a fortunate situation, a sinkhole of this size could have easily swallowed up an entire building.
World’s Largest Sinkhole
The world’s largest sinkhole is located in Egypt, just outside of Cairo. It is, as you’d expect from the world’s largest sinkhole, extremely large. At 120 kilometers wide and 80 kilometers long and 200 feet deep, the Qattara Depression is pure sinkhole terror.
Florida Sinkhole Alley
Because much of Florida is built on limestone, it is known as “sinkhole alley.” Sinkhole science and studies are often centered in Florida due to the notability and precariousness of the state in concern with sinkholes. These days, in Florida, sinkholes are really just a part of life. They consistently contribute to broken roads and taped off apartment complexes.
The Florida counties most specifically tied to the sinkhole alley term are Hillsborough, Hernando, and Pasco, all of which are located near the central portion of the state and Tampa.
Between 2006 and 2010, Florida went from 2,300 sinkhole claims to 6,700 sinkhole claims. All totaled, the state served up more than $1.4 billion in sinkhole insurance claims.
Florida Sinkhole Map
These are sourced from the usf.edu website. They are likely outdated. I’ve included the infamous sinkhole alley counties.
Can You Prep For a Sinkhole?
Not really. If a sinkhole wants to pull your card, you pretty much weren’t meant to be any longer. There are a great deal of scientific research efforts aimed at helping with sinkhole prediction, but it is largely without any real usefulness yet so far.
The best things you can do are as follows:
Know sinkhole information. If you are warned you are living on top of a potential sinkhole, take it very seriously. Even if you aren’t warned, just understanding the facts listed above can help you use your gut instincts to decide if you are potentially at risks. If you see any places in the ground that seem to be collapsing, evacuate and call for help in further investigating the situation. Sinkhole experts can come out and have a look.
If you see things like trees and fence posts collapsing, that could be a sinkhole warning. Other sinkhole warnings can be cracked floors, water that appears cloudy in your well, pavement cracks, and dying vegetation.
Have a bug out bag. I can’t say this enough, but having a bug out bag is always good form for a variety of survival situations. If a sinkhole does happen to occur where you are at, you will likely need first aid, or you will need to flee.
If you live on property that previously had a sinkhole prepared, consider calling a professional out to surmise the situation. Don’t be afraid of second opinions.
Always, always, always evacuate if you think you might be on, or near, a sinkhole.
Author: Jim Satney
PrepForThat’s Editor and lead writer for political, survival, and weather categories.