DAVID HARDY / SCIENCE PHOTO LIBRARY DAVID HARDY / SCIENCE PHOTO LIBRARY
Diagram showing how ground deformation may be used to predict volcanic activity. In the top frame, the ground is uplifted over a rising magma chamber due to the pressure of lava. This uplift continues to the point at which the lava finally breaks through to the surface and erupts (centre). After the eruption, the lava pressure drops and the ground returns to its original position, albeit with a new cover of lava (bottom frame). Such ground motion is most evident on shallow, shield type volcanoes such as those in Hawaii.
Model release not required. Property release not required.