Where Volcanoes Are Born Most volcanoes form at the boundaries of Earth's tectonic plates, which are huge slabs of crust and ...

California has seven active volcanoes, each with a unique eruption history, categorized by type and threat level. The USGS monitors these volcanoes, providing information to authorities and the public ...

Smoke billows from the mouth of Mt. Shasta like a thunderous cough. Within moments, clear skies turn gray, and the sun vanishes behind thick, shifting layers of volcanic gas and ash. Visitors snap ...