March 1965 eruption of Kilauea volcano and the formation of Makaopuhi Lava Lake

From March 5 to 15, 1965, Kilauea volcano erupted over 15 million cubic meters of tholeiitic basalt along the upper east rift zone between Makaopuhi and Kalalua craters. A pond of basalt 83 meters deep was left within the west pit of Makaopuhi crater. The eruption was preceded by inflation of the Kilauea summit and was accompanied by collapse of the summit. Observed horizontal, vertical, and tilt changes accompanying inflation of Kilauea before and after the eruption cannot fit any simple model for inflation of a single magma chamber. Data for the collapse are even farther from agreement with the draining of a single chamber. Seismic activity was exceptionally low in the months preceding the eruption and during the eruption. Amplitude of harmonic tremor correlates with the rate of fountaining during the eruption. Temperatures of the erupted lavas have been estimated at 1190°–1200°C by extrapolation of thermocouple data obtained in Makaopuhi lava lake. A comparison with temperatures of other Kilauea eruptions measured by optical pyrometer indicates that the best optical pyrometry yields temperatures 35°–75° lower than the true temperature of eruption. The erupted lavas were olivine-poor tholeiitic basalts. Lavas erupted at successively later times down rift are shown to be differentiated from the lavas erupted at Makaopuhi crater by removal of olivine, clinopyroxene, and minor plagioclase during transport in the rift zone.