Sinkholes form when layers of soil and rock underground collapse into empty spaces below them. The Alton sinkhole was caused by the crumbling of the earth above an underground mine. That’s a place where people dig for minerals and other materials.

Sinkholes can swallow up sports fields, roads, and buildings. If people fall in, they can get injured or even die. Scientists are working to understand where sinkholes are most likely to form—and how to keep them from doing major damage.

Sinkholes form when there are empty spaces below ground. Then layers of soil and rock above collapse. Crumbling earth over an underground mine caused the Alton sinkhole. A mine is a place where people dig for minerals and other materials.

Sinkholes can swallow up sports fields, roads, and buildings. People can get hurt or even die if they fall into one. Scientists are working to learn where sinkholes might form. They want to prevent them from doing major damage.

Sinkholes usually form naturally. But human activity can also contribute to them. Many of the sinkholes that show up in cities and towns are at least partly caused by humans, says Doctor.

When people drill in the ground, they can disturb the water underneath. Drilling can cause water to collect or travel to areas likely to break down. Leaks in pipes can also create gaps in soil and rock. Mines can create problems too if they are not properly managed. Recently, sinkholes have formed over abandoned mines in New Jersey and Pennsylvania.

While officials know that the Alton sinkhole formed over a mine, they’re still determining the cause of the collapse. “Water may have dissolved a narrow space in the roof of the mine,” says Bob Bauer, a geologist who has studied the area. That water could have eroded the soil and weakened the rock, creating the right conditions for a sinkhole.

Sinkholes usually form naturally. But human activity can also cause them. Sinkholes show up in cities and towns. They’re at least partly caused by humans, says Doctor.

People drill in the ground. That can disturb the water underneath. Drilling can cause water to collect in areas likely to break down. Or it can travel to these areas. Leaks in pipes can also create gaps in soil and rock. Mines can create problems too. So they need to be properly taken care of. Sinkholes have formed over mines. This happened recently in New Jersey and Pennsylvania.

Officials know the Alton sinkhole formed over a mine. But they’re still determining the cause of the collapse. “Water may have dissolved a narrow space in the roof of the mine,” says Bob Bauer. He’s a geologist who has studied the area. That water could have eroded the soil and weakened the rock. That created the right conditions for a sinkhole.

There’s no way to know exactly where the next sinkhole will open up. But scientists can predict where they are most likely to form. Doctor recently created a map showing the areas in the U.S. most at risk for sinkholes (see “Sinkhole Hot Spots”). He used data such as each region’s type of bedrock, soil, and rainfall totals.

Understanding whether an area is at risk for sinkholes can help people make decisions that can reduce damage. They can avoid drilling or mining in certain areas, or take steps to prevent flooding.

So should you be worried about being swallowed by a sinkhole? Nope, says Doctor. Most form gradually. Plus, the chance of one forming in most neighborhoods is very small.

“Sinkholes are spread across the landscape,” says Doctor. “They’re forming all the time, but they’re not really harming a lot of people.”

There’s no way to know exactly where a sinkhole will happen. But scientists can predict where they are most likely to form. Doctor recently looked at different regions in the U.S. He studied their bedrock, soil, and rainfall totals. Then he created a map. It shows the areas most at risk for sinkholes (see “Sinkhole Hot Spots”).

People need to know this information. It can help them make decisions to reduce damage from sinkholes. They can avoid drilling or mining in certain areas. Or they can take steps to prevent flooding.

Should you be worried about being swallowed by a sinkhole? Nope, says Doctor. Most form slowly. Plus, the chance of one forming is very small.

“Sinkholes are spread across the landscape,” says Doctor. “They’re forming all the time. But they’re not really harming a lot of people.”