Logbook: August 4

47°57.015'N / 129°5.83'W

Arrival at Endeavour Ridge
Bill Chadwick, Chief Scientist

Map showing some of the venting areas of the main Endeavour hydrothermal site. . (click image for larger view)

During this expedition we will be working at 2 or 3 sites on the Juan de Fuca Ridge, the seafloor spreading center located about 300 miles off shore of Oregon and Washington.  Our first destination is the Endeavour Segment, followed by Axial Seamount, and the third (time permitting) will be the Cobb segment.  All three of these sites have active hydrothermal vents on the seafloor.

After a smooth ride out of the Columbia River into the North Pacific. we arrived at the Endeavour and encountered some bad weather with winds over 30 kts. For safety, the Jason ROV dive needed to be postponed until the winds subsided. Under these conditions the best plan was to conduct a vertical cast CTD (Conductivity, Temperature, Depth recorder) over the Mothra Hydrothermal Field at Endeavour.

The CTD will give us a view of how the hydrothermal plume over that vent field has changed in intensity, extent, and chemistry since last year.  After the CTD, the weather conditions had improved enough for Jason to dive.  We will report on our dives at Endeavour soon.