In Pu‘u ‘Ō‘ō, a small lava pond was still "gas pistoning"

In Pu‘u ‘Ō‘ō crater, a small lava pond (about 5 meters, or yards, wide) continued to be active and was still "gas pistoning" today. Gas pistoning is a cyclic rise and fall of the lava pond surface due to gas buildup and release. During the fall phase, intense spattering disrupts the lava pond surface and releases the accumulated gas. Each cycle lasted about five to ten minutes.