Photograph by R.W. Decker on 16 June 1983
Photograph by R.W. Decker on 16 June 1983
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.