What are volcanic arcs?

Volcanic arcs are chains of volcanoes that form when one piece of Earth’s crust moves under another.

Imagine you have a plate of cookies, and you push one cookie under another, like when you slide your hand under a napkin to move it. This is what happens with the Earth's plates, huge slabs of rock that float on the hot, soft layer beneath them. When one plate slides under another, it can cause volcanoes to pop up in a line, just like cookies might crumble or rise in a row if you push too hard.

When the bottom plate moves down, it gets squeezed and heated. This makes melted rock, called magma, which then rises through the top plate. As the magma reaches the surface, it becomes lava and forms volcanoes.

These volcanoes often form a line, like steps in a staircase or a row of cookies being pushed up, creating what we call a volcanic arc.

You can think of it like a cookie sheet with melted chocolate, as the chocolate rises through the cracks, it creates little bumps and hills on top. That's how volcanic arcs form!