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 massive rafts floating ...

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 dropped ...

Learn how Mount Etna stands apart from most volcanoes, having been formed by pockets of magma held in Earth's upper mantle. Europe’s tallest active volcano, Mount Etna, may belong to an obscure group ...

Volcanoes emit smoke. Beneath a volcano lies a huge chamber filled with liquid magma. A series of earthquakes means an eruption is imminent. And if a "supervolcano" like Yellowstone were to awaken, a ...