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Anatahan Volcano Update, July 2-4 On July 2, we visited Anatahan again by helicopter. Eruptive activity at the east crater appeared to be as low as at any time since the eruption began. We estimated the height of the plume to be about 3,000 feet above sea level. The plume was thin and had a low content of ash. It rose slowly vertically and did not appear to be dispersed very far downwind, despite light trade winds coming from the east-northeast. East and northeast of the island, the fume cloud was thinner and much less impressive than it had been on previous visits. We still were unable to see all the way to the crater floor, but several small vents emitting fine-grained ash and fumaroles producing white steam were visible on the lower crater walls. We briefly visited the abandoned village on the northwest coast of Anatahan and retrieved about 5 mm of ash that had fallen into a collecting pan since June 21. Rainwater had redistributed the original fall deposit, so an accurate thickness could not be determined. No ash fell during our 30-minute stay. We also landed at the active seismic station on the east end of the island and found no visible changes since the last visit. Volcanic tremor at Anatahan persisted during July 2-4 at a relatively low level similar to that of the previous reporting period. Contact persons:
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U.S. Department of the Interior, U.S. Geological Survey, Reston, Virginia, USA
