Anatahan Volcano Update
Anatahan Volcano Update for May 7, 2004
Submitted Friday, May 7, 2004 at 1200 local Anatahan time
On April 24, a moderate eruption began at Anatahan, sending steam and
ash to ~2,000 ft (600 m). A small dome was observed within the inner
crater a day or two later. On April 28, the seismicity peaked at a high
for the year, and the dome increased in size. Since then the
average seismicity level first decreased somewhat for a few days, then
increased again but has been significantly more variable. Explosion signals have become less frequent, averaging one event
every two minutes, but have become larger, commonly reaching M ~3. A few
hours ago, there was a remarkable couple of hours of nearly total calm
beginning at 2230. Steam
and ash are still rising to a few thousand feet. The eruption could
become more explosive at any time with little or no warning.
The Emergency Management Office, Office of the Governor, CNMI, has
placed Anatahan Island off-limits until further notice and concludes
that, although the volcano is not currently dangerous to most aircraft
within the CNMI airspace, conditions may change rapidly, and aircraft
should pass upwind of Anatahan or >30 km downwind from the island and
exercise due
caution within 30-50 km of Anatahan.
Contact persons:
Juan Takai Camacho, Geophysical Seismic Technician, EMO Saipan; tel:
(670) 322-9528, fax: (670) 322-7743, email: juantcamacho@hotmail.com
Ramon Chong, Geophysical Instrument Specialist, EMO Saipan; tel: (670)
322-9528, fax: (670) 322-7743, email: rcchongemo@hotmail.com
Frank Trusdell, Geologist, USGS; tel: (808) 967-8812, fax: (808) 967-8890,
email: trusdell@usgs.gov
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