The 1962 flank eruption of Kilauea volcano and structure of the east rift zone

On December 7–9, 1962, a small flank eruption occurred on the upper part of the east rift zone of Kilauea volcano. The six eruptive fissures, which show a right-offset en echelon pattern, extend more than 2 miles from Aloi crater eastward to the west slope of Kane Nui o Hamo. The total volume of erupted lava was small (426,000 cubic yards) and much of it, which ponded temporarily in Aloi crater, drained back into the eruptive fissure on the floor of the pit crater. Tilt measurements show that a collapse of the summit of Kilauea occurred during the eruption, and precise leveling of the rift zone indicates that absolute uplift of the ground near the eruptive region exceeded 2.5 feet. The changes in elevation presumably resulted from a transfer of magma from the reservoir beneath the summit to the upper east rift zone. Mapping of the upper rift zone indicates that fissure vents and cinder cones are generally north of pit craters, and this suggests that the rift zone dips southward. Apparent tensional opening of the rift zone, which allows magma to drain from the summit reservoir, probably results from a combination of (1) southward movement of the flank of the volcano south of the rift zone under the influence of gravity and (2) inflation of the dipping rift zone by magma from the summit reservoir.