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Anatahan rumbles anew
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Posted on Jun 13 2005
Volcanic eruption on Anatahan escalated over the weekend and threw out thick ash clouds to 45,000 feet in the air Saturday, posing a threat to at least two aircraft passing through the Northern Marianas’ airspace.
The U.S. Geological Survey and the Emergency Management Office consider Saturday afternoon’s activity as the second strongest eruption of Anatahan in recorded history following the record-high of 50,000 feet last April 6.
Last Thursday, the volcano began to unleash its fury by spewing out ash to 30,000 feet, resulting in ashfall in the Northern Islands, particularly Alamagan, Pagan, and Agrihan.
By Saturday, tremor levels on Anatahan remained high, with small long-period earthquakes occurring frequently. The strong explosions occurred at about 4:22pm Saturday and lasted for about three minutes, the agencies said. Smaller explosions that lasted about two minutes followed about nine minutes later.
“The dense ash cloud from those two eruptions rose to 45,000 feet as verified by two passing aircraft, the second highest eruption of Anatahan in recorded history after the eruption to 50,000 feet on April 6 of this year,” the agencies said. “That ash cloud reached a maximum extent of 36 nautical miles in length and quickly detached from the island as the eruption waned.”
The volume of ash emitted by the volcano has yet to be ascertained. During the April 6 eruption, the agencies said the volcano expelled about 50 million cubic meters of ash.
The agencies reported no ashfall on Saipan, reporting that the thick ash plume moved westerly before dissipating.
They said tremor levels on Anatahan declined after Saturday’s strong eruption, but added that the volcano continued to emit ash to 14,000 feet. “The ash plume [fanned] out about 190 nautical miles to the west and southwest from the island.”
Yesterday morning, the volcano emitted ash to 10,000 feet, which extended southwest of the island.
The EMO cautioned aircraft that conditions could change rapidly, advising aircraft to pass upwind of Anatahan or beyond 10 nautical miles downwind from the island and reminding them to exercise due caution within 10 nautical miles.
