This month in Hawaiian volcano history . . . .

May 19, 1916 Mauna Loa's smallest flank eruption on record began on the volcano's southwest rift zone at an elevation of 3,355 m (11,000 ft). Two days later, a more vigorous fissure erupted about 1,200 m (4,000 ft) lower on the rift zone, sending two main flows of 'a'ā lava downslope at speeds of up to 8 km (5 mi) per hour. Neither flow reached the ocean, but both destroyed pasturelands and caused some Ka'ū and South Kona ranchers to evacuate their homes. The eruption ended on May 31. May 10, 1924 Kīlauea's first explosive eruption since about AD 1790 began on this night. Following small events on May 11-12, a series of violent explosions began on May 13. The intensity peaked on May 18, when multiple explosions sent black clouds of dust more than 6,500 m (21,000 ft) high and blasted a 10-ton boulder about 1,050 m (3,500 ft) from the crater rim. By the time the eruption ended on May 27, Halema`uma`u was twice its former diameter and triple its former depth. May 31, 1954 This 3.5-day-long Kīlauea summit eruption began around 4:00 a.m., when a series of fissures cut across the Halema'uma'u Crater floor, spewing lava up to 30 m (100 ft) above the crater rim. Lava also poured from a crack in the northeastern crater wall, cascading into the surging lava pool on the crater floor. The fissure soon extended up the crater wall and across Kīlauea's caldera floor to the northeast. By mid-morning, the eruption waned, with only weak spattering and lava outflow continuing until June 3. May 24, 1969 The Mauna Ulu eruption on Kīlauea's east rift zone lasted five years. During the first 2.5 years, the fissure eruption was almost continuous and often spectacular. After a 3.5-month pause in activity (October 1971 to February 1972), the eruption resumed and continued to July 1974, with lava flows covering 17.6 square miles and adding about 230 acres of new land to Hawai'i Island. It was Kīlauea's longest and largest east rift zone eruption in recorded history until surpassed by the ongoing Pu`u `Ō `ō eruption.