East end of 'Alae Crater after catastrophic draining on Aug. 4, 1970

East end of 'Alae Crater after catastrophic draining on August 4, 1969. The entire crater was nearly full of lava erupted in February 1969 and later by Mauna Ulu, most recently on August 3. Early on August 4, most lava in the crater drained away in about 30 minutes as new ground ruptures opened, possibly because of the weight of the new crater fill, which was about 80 m (260 ft.) deep. This photo, taken at 1530 that afternoon, shows the high lava mark left after the draining and the gash at the location of a large crack (the graben in subsequent images) that carried some of the lava out of the crater.