From 1823 to 1924, there was almost continuous eruptive activity within Halemaʻumaʻu crater. During this period, there were 15 eruptions and 11 subsidence events at the summit.
In February 1924, the lava drained out of Halemaʻumaʻu and began to migrate down the east rift zone. On April 23, seismic activity peaked that led to ground cracking, faulting and coastal subsidence in lower Puna. No lava came to the surface in this area, but there may have been an undersea eruption.
The Halemaʻumaʻu crater was 377 ft (115 m) deep following the draining of the lava lake. Through a serious of collapses that began on April 29, the crater deepened to 690 ft (210 m) by May 7. Steam and pressure built as the buried hot rocks became saturated from the water table. For 18 days, hundreds of steam explosions from Kīlauea hurled mud, debris, and boulders great distances.
The first explosion occurred on the evening of May 9. Larger explosions followed on May 13, and the crater continued to collapse. From May 9 to May 27, a series of more than 50 explosions doubled the diameter of the crater to about 3,289 ft (100 m) and deepened the crater to about 1300 ft (400 m). Steam explosions hurled mud, debris, and hot rocks weighing as much as 8 tons (7,000 kg) two-thirds of a mile (1 km). The largest explosion occurred on May 18 that killed a photographer by falling debris.
Explosive eruptions on Kīlauea have occurred in the past and will almost certainly occur in the future.