VHP Photo Glossary: Lava surge
Intermittent surges or accelerations in the forward advance of lava can occur when the supply of lava to a flow front suddenly increases or a flow front gives way. The supply of lava may increase as a consequence of a higher discharge of lava from the vent, a sudden change in the vent geometry so that a great volume of lava escapes (for example, the collapse of a vent wall), or by the escape of ponded lava from along a channel. Lava surges may be accompanied by thin, short-lived breakouts of fluid lava from the main channel and flow front.
An increase in lava supply to the front of an `a`a flow caused the lava surge shown here in the Royal Gardens subdivision on Kilauea Volcano, Hawai`i. The glowing part of the surge is 6-7 m tall and the flow front advanced at a rate of 33 m/min, compared to 1.5 m/min before the surge.