Question: How are sinkholes produced? And why?

Jemma Rowlandson answered on 17 Jun 2014:

Hello!

This is an awesome question! Right so sinkholes can form in several ways, the most common is when acidic water dissolves away rock beneath the ground. They usually appear in places which have a lot of soluble rock, like limestone or chalk.

In these areas rain soaks through the ground and reacts with any decomposing plants in the soil. This reaction causes the water to become more acidic.

Once the acidic water reaches the soluble rock beneath the ground it starts to erode it, causing holes to form beneath the surface. These holes can form over hundreds or thousands of years creating large caverns.

The surface above the cavern stays in tact until it is no longer supported, because of the growing cavern below it. This is when you get a sudden collapse of the surface, forming a sinkhole.

Sinkholes can form quickly in only a few minutes, or they can take a few hours. They can also be quite small (a meter or so) or very large, some have been known to swallow a house!