"More than 1 million cubic yards of tholeiitic basalt was erupted from the upper east rift zone of Kilauea Volcano during a brief 6-hour period on December 24 and 25, 1965. The eruptive fissures opened in an en echelon zone about 2 miles long, from Aloi Crater eastward to Kane Nui o Hamo. The vigorous early stage of the eruption formed a 47-foot-deep lava lake in Aloi Crater and flooded about 150 acres of forest to the east. At a later stage, withdrawal of magma into the source fissures and other cracks drained the lava lake in Aloi Crater and considerably reduced the volume of lava in the flows remaining on the surface. Measurements of ground tilt show that Kilauea summit inflated before the eruption, and that it abruptly deflated just before and during the eruption. Significantly, the summit continued to deflate for an additional 10-hour period after the eruption had ended. Precise leveling suggests that the summit of the volcano did not collapse simply, and that small subsidiary areas of collapse lay about 1.5 km north and 2 km southeast of Halemaumau. The eruption marked only the beginning of a major seismic crisis that lasted for more than a week. Thousands of earthquakes were recorded, and preliminary results indicate that most of the epicenters lay in a narrow area extending from the upper east rift zone westward along the Koae fault zone into the Kau Desert. Hundreds of ground cracks and faults opened in this area, and precise leveling has shown that the area of cracking locally subsided nearly 6 feet. The eruption ended as the tempo of ground cracking and earthquakes was just reaching a maximum."
Geological Survey Professional Paper 607
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