DAVID HARDY / SCIENCE PHOTO LIBRARY DAVID HARDY / SCIENCE PHOTO LIBRARY
Diagram of two causes of volcanic eruptions. At left, a large magma chamber causes upswelling of the overlying crust. The crust splits, and magma may rise due to its own pressure to the surface through the fracture. At right, the land either side of a volcano is moving apart. This re-opens a vent linking the magma chamber to the surface. Dissolved gas in the magma forms bubbles which rise up the vent, carrying lava with them.
Model release not required. Property release not required.