Study area location map generated by shipboard GIS
WECOMA Morning Report: 15 Apr 96 Rcvd 1526Z/4.146 Mhz
Lat.: 42-29.6N Long.: 126-56.9W
Wx: Cldy Wind: 195-15 kn Sea: 2 ft
.
Swell: 240-7 & 170-6 ft Baro.: 1008.3 mb Temps: 53/53 F
Fuel: 36,774 gal. Lube: 1,211 gal.
Sci. Ops.: Completed camera tow over weekend with good results.
Currently doing toyo CTD.
Comments: ETA for WECOMA in Newport is 1000 on Tuesday, 16 April -
Weather prediction is for rain and gale force winds at this time.
WECOMA Morning Report: 12 Apr 96 Rcvd 1503Z/4.146 Mhz
Lat.: 42-39.9N Long.: 126-43.6W
Wx: Cldy Wind: 270-24 kn Sea: 5 ft.
Swell: 280-12 ft. Baro.: 1019.2 mb Temps: 51/48 F
Fuel: 38,674 gal. Lube: 1,234 gal.
Sci. Ops.: Ceased operations during the night due to heavy seas. Seas
expected to die down, will resume with toyo CTD this morning.
Comments: Current ETA for WECOMA in Newport is 1200 on Tue., 16 Apr -
this is subject to revision.
WECOMA Morning Report: 11 Apr 96 Rcvd 1507Z/4.146 Mhz
Lat.: 42-27.4N Long.: 126-5.8W
Wx: Ovcst-Mist Wind: 200-27 kn Sea: 5 ft.
Swell: 260-6 ft. Baro.: 1015.3 mb Temps: 54/53 F
Fuel: 39,274 gal. Lube: 1,234 gal.
Sci. Ops.: Completed second camera tow with good results - addl info
will be sent to PMEL via INMARSAT. Presently conducting toyo CTDs with
hydro winch. Payout rate must be limited to about 17 m/min to avoid
tripping out winch controller but this is not limiting scienctic
operations - getting good results. Will continue CTD operations - wx
currently too rough for camera ops and expected to get worse over next
several hours.
WECOMA Morning Report: 10 Apr 96 Rcvd: 1543Z/4.146 Mhz
Lat.: 42-37.1N Long.: 126-48.5W
Wx: Light Rain Wind: 160-15 kn Sea: 2 ft.
Swell: 270-6 ft. Baro.: 1018.1 mb Temps: 50/50 F
Fuel: 39,824 gal. Lube.: 1,254 gal.
Sci. Ops.: Presently conducting second camera tow. Will recover at 1000
and commence toyo with hydro winch - will be first operational use since
repaired. Operations proceeding smoothly.
WECOMA Morning Report: 09 Apr 96 Rcvd 1525Z/4.146 Mhz
Lat.: 42-48.0N Long.: 126-42.9W
Wx: Cldy Wind: 270-11 kn Sea: 1 ft.
Swell: 260-5 ft. Baro.: 1016.4 mb Temps: 52/50 F
Fuel: 40,274 gal. Lube: 1,254 gal.
Sci. Ops.: Doing "toyo" CTD using trawl winch. Camera ops yesterday
partially successful but making adjustments. Hydro winch (main CTD winch
which had a controller failure Sunday night) "jury-rigged" and tested to
2,000m last night without problem, will be used for next CTD cast.
Comments: Need wall mount cans for elec. htrs. for master/mate
rooms, wont need evap. heat exc. cleaned (onboard cleaning sufficient),
MSD pump OK - just needed adjustment.
STATUS REPORT #3-GREAT CRUISE II, Wecoma 4/13/96
From: Jim Cowen, Bob Embley, Ed Baker and Scientific Party of GREAT II
Aloha,
Subsequent to our previous message: After about a 12-hour weather delay,
we were back to work with another tow-yo, towing along the east side of
the axial valley from the Narrrowgate south-southwest to the mid-point of
the northern Gorda's southern "basin" then crossing the axial "basin" at an
oblique angle and partially up the west axial wall. Cumulatively, the last
two tow-yos reveal a plume 7 nm along axis and at least 5 nm wide across axis.
The western boundary is still unknown, and the vertical extent is roughly
2600-3000 m. Weak plume signals have been detected as shallow as 2100 m over
the central basin. It appears to spread vertically against the west valley
wall and extends to the east past the center of the "basin", with sharp
lateral gradients in temperature and light scattering anomalies. Further
tow-yo and chemical analysis work will hopefully help distinguish between
an event versus chronic-type plume origin. The plume is constrained
laterally by the axial walls affording a potentially fascinating study site
for chemical and physical changes in a plume.
The most recent camera tow has also discovered additional temperature anomalies near the seafloor (within 5 m), north of the previously photographed new lava flow on the west side of the southern Narrowgate region. The two areas may be part of the same eruptive line. The camera underwent a quick turn around and is currently continuing its survey of this region. Incidentally , the versatile camera system succeeded in dredging a nice boulder of what appears to be fresh lava.
Study area location map generated by shipboard GIS
STATUS REPORT #2--GREAT CRUISE II, Wecoma (received 1000, 4/11/96)
From: Jim Cowen, Bob Embley, Ed Baker and Scientific Party of GREAT II
Subsequent to our previous message, the GREAT II party has made several interesting discoveries, despite continuing troubles with the ship's winches. It should be noted that the captain and crew of the Wecoma have gone out of their way to correct the winch problems and to accommodate the needs of our scientific operations.
A portion of film from the camera tow (#2) was developed on board. The resulting images revealed a very fresh lava flow on the west side of the axial valley, southern portion of the Narrowgate (42 40'N; 126 47.2'W). These photos were taken coincidently with a bottom temperature anomaly. Several images show the boundary of the newer flow overlaying the older flows. The next camera tow (#3) will attempt to better define the lateral extent of the flow. Tow-Yo #2 started over the southern portion of the Narrowgate, proceeding south (heading ~187 deg.). The early part of the tow showed the same weak plume observed during the first tow, sustained for several miles to the south of the Narrowgate. This plume signal dissipated over several additional miles before the tow abruptly encountered a substantial plume at 42 34'N; 126 51'W. This plume had strong temperature (~.03 deg.), light scattering, Fe and Mn anomalies, easily the most pronounced observed during the present cruise. This strong plume was sustained over a track line that retraced the series of stations #3, 4 and 5 from the first GREAT I cruise, at which time no anomalies were found.
Our weather forcast is building winds and seas. We are hoping that this is not so. Ah, but alas it is. Winds are 35 mph, gusting to 40.
STATUS REPORT # 1 -- GREAT CRUISE II (WECOMA) (received 4/10/96)
FROM: JIM COWEN, BOB EMBLEY, AND SCIENTIFIC PARTY GREAT II
TO: STEVE HAMMOND, CHRIS FOX, DAVE EPP AND ALL INTERESTED PARTIES
To date we have conducted 11 CTD casts, two camera tows, and one CTD Tow-Yo. Problems with main hydrographic winch and limitations of backup trawl winch have hampered CTD operations to date. Megaplume search casts were on northern Gorda Ridge 10 to 20 nautical miles from GREAT 1 megaplume center. No hydrothermal signals were detected. The camera tow passed over a significant near-bottom temperature anomaly at 42 40'N; 126 47.2'W on west side of axial valley. We have not seen images of vent to date because of problems with camera system but hope to from second camera tow. Tow-Yo along west side of axial valley detected weak hydrothermal plumes (max. temp. anomaly about 0.02 deg and low backscatter) beginning at 42 41'N southward to 42 38'N where Tow-Yo ended. SUAVE shows correlation of temperature maxima with Fe and Mn anomalies. Plan is to trace limits of source with camera and to continue axial Tow-Yo to south.