Lava flow animation

This animation shows the sequence of events that occurred during the 1998 eruption, when the rumbleometer instrument was caught in the lava flow.

A description of the sequence of events in the animation:

(1) The eruption begins when a dike reaches the surface and lava erupts onto the seafloor. Initially, lava spreads out as a thin sheet with lobate morphology. Lava flows under the rumbleometer instrument.

(2) Next, the lava flow thickens and inflates (the upper solidified crust is uplifted by the still-molten interior of the flow). Lava pillars form during this stage, and the rumbleometer is uplifted by the flow's upper crust.

(3) The sheet flow inflates to a thickness of 3-4 meters (9-12 feet). Then, the eruption began to wane and the lava supply from the eruptive vents stops.

(4) Subsidence of the still-molten flow interior begins due to lava drain-back. This removes support for the upper solid crust of the sheet flow causing it to collapse where it is unsupported from below. New crust forms on the subsiding molten lava with ropy, lineated, or jumbled morphologies. After collapse, lava pillars are exposed within the collapse areas. Pillar tops and the uncollapsed margins of the flow preserve the initial lobate morphology.

(5) Finally, all the lava solidifies. The whole sequence represents about 2 hours.

Be sure to read The rumbleometer story and check out the Rumbleometer Virtual Site for more information.