A small explosion from Kīlauea's summit lava lake in Apr. 2015 was ...

Rocks from the crater wall fell into the summit lava lake and generated an explosion that threw large fragments of molten lava onto the rim of Halema‘uma‘u Crater, 85 m (280 ft) above the lake. Gas in the lava lake was rapidly released during the 10:20 am explosive event, causing the lava lake surface to drop a few meters (yards) after the explosion.