Where Volcanoes Are Born Most volcanoes form at the boundaries of Earth's tectonic plates, which are huge slabs of crust and upper mantle that fit together like puzzle pieces. Think of these plates as ...

Some volcanoes, such as the Cascade volcanoes up in Washington and Oregon, are of the type called a stratovolcano. These steep volcanoes sometimes erupt explosively and other times have calmer lava ...

The explosiveness of a volcanic eruption depends on how many gas bubbles form in the magma – and when. Until now, it was thought that gas bubbles were formed primarily when the ambient pressure ...