What are calderas?

A caldera is like a giant bowl that forms when a volcano explodes and collapses.

Imagine you have a big bowl full of soup, that's the inside of the Earth before it erupts. Now, if someone takes out all the soup in one go, the bowl would collapse in on itself, leaving a huge empty space. That’s what happens with a caldera.

When a volcano explodes very strongly, like when it throws out lots of lava and rocks, the top of the volcano can fall down into the empty space below. This makes a big round hole, which is the caldera.

You can think of it like this: if you have a cookie jar and you take out all the cookies at once, the jar might collapse in on itself. That's kind of what happens to a volcano when it forms a caldera.

Sometimes, after the explosion, water can fill the caldera, making it look like a lake or even a whole new island!