U.S.
Dept. of Commerce / NOAA / OAR
/ PMEL / VENTS
Program / Axial Seismic Event
Axial Seamount Volcanic Event - Past Updates
UPDATE 16 February 1998, 0900PST -Nearly continuous CTD operations
throughout the weekend despite 10-18' seas and 25-40kt winds. Strong hydrothermal
signals from southern portion of caldera but no hydrothermal signals in southern
portion of seismicity swarm areas. Complete details available in final
science report. Wecoma arrives in Newport at 1145PST, 16 February after
transit in very strong winds and heavy seas resulting in a blown out window
in aft control station.
UPDATE 13 February 1998, 0900PST - VERY strong plume detected
with CTD at southern end of volcano caldera. No hydrothermal signal
detected yet near center of concentrated down rift seismicity. More CTD
casts planned near southern seismic swarm, weather permitting. Detailed
science report avialable now.
UPDATE 12 February 1998, 1000PST - WECOMA at 45 55.6N 129 55.9W experiencing seas of 12-17', wind 40-50kts. Conducting CTDs with little problem. A detailed cruise report to date is now available.
UPDATE 11 February 1998, 0931PST - WECOMA at 45 55.8N 129 58.5W
experiencing seas of 20-25', wind 50kts. All OBHs deployed last night.
UW CTD not working, moving out of way to use OSU CTD.
UPDATE 10 February 1998, 1220PST - WECOMA 0200PST, seas 30',
wind 70kts. 0900PST conditions improved to seas 12-20', wind 35kts.
Ship enroute to site. 1220PST, ship at 45 22.8N 128 18.2W making
11.5kts heading for first OBH deployment site w/ETA at 2000PST.
UPDATE 9 February 1998, 1345PST - R/V WECOMA left Newport 1040PST.
Ship will be on site 10 February 1998.
UPDATE 8 February 1998, 1230PST - WECOMA continues preparations
for departure on 2/9 with full scientific complement. Eight Ocean
Bottom Hydrophones, 3 neutrally buoyant RAFOS floats, and full water
sampling gear are onboard. Weather conditions are extremely poor.
UPDATE 6 February 1998, 1630PST - Routine web site updates will be discontinued. Results from Wecoma will be posted as they are received.
UPDATE 5/6 February 1998, 0930PST - Seismic activity has
effectively ceased after ten days and nearly 8,200 earthquake
detections. Response cruise planning continues for 2/9 departure from
Newport.
UPDATE 4 February 1998, 0930PST - Seismic activity has subsided
significantly, with only a few events/hour. SOSUS array was restored at
0300Z and is recording. New epicenter map under seismicity page shows
time dependence of activity. Response cruise planning continues for 2/9
departure from Newport.
UPDATE 3 February 1998, 0900PST - Seismic activity continues at
a reduced level, with 3-5 events/hour. One SOSUS array remains down,
limiting the ability to accurately locate events. Response cruise
planning continues.
UPDATE 2 February 1998, 0830PST - Seismic activity continues at
a reduced level, with 5-10 events/hour. Currently, one SOSUS array is
down, limiting the ability to accurately locate events. Response cruise
planning continues.
UPDATE 1 February 1998, 1300PST - Seismic activity continues at
a reduced level, with 8-10 events/hour. Three primary SOSUS arrays were
disabled during most of Julian Day 31, and currently one array is down.
This limits the ability to accurately locate events and may affect the
apparent number of events. System should be repaired early next week.
UPDATE 30 January 1998, 1600PST - Seismic activity continues
with 20-30 events/hour. All systems remain fully operational. Wecoma
cruise planning continues. Page updates will be only minor until Monday.
UPDATE 29 January 1998, 1200PST - Epicenter map and time/latitude map have been updated. Migration appears to have stopped at 45 28'N and focus near 45 30'N.
UPDATE 29 January 1998, 0900PST - Oregon State University Marine
Superintendent Fred Jones reports that NSF has approved seven days of
Wecoma time for a field response to Axial Seamount. Tentative dates are
February 9-16 with Newport, Oregon ports.
UPDATE 29 January 1998, 0830PST - After slowing to about 25
events/hour last night, activity picked up again to about 50
events/hour within the last hour. A total of over 6,000 earthquakes
have been detected. All Navy and NOAA monitoring systems continue fully
operational. Indications are positive for a field response using the
OSU R/V Wecoma. Epicenter maps and histograms will be updated later
this morning.
UPDATE 28 January 1998, 1500PST - Intense activity continues on
the south flank of Axial Seamount with 30-40 events per hour recorded;
epicenter migration to the south continues, with epicenters located as
far south as 45 28'N. All Navy and NOAA monitoring systems are fully
operational. Another large magnitude earthquake (mb=4.7) was recorded
by the land network. Planning continues for a field response using the
OSU R/V Wecoma.
Last Updated: 2/23/98 0900PST
Address inquiries to:
Event Detection
Bob Dziak - Seismologist
Event Response
Jim Cowen - University of Hawaii - jcowen@soest.hawaii.edu
Bob Embley - NOAA/PMEL