End of VISIONS '13 Leg 3

Sunday, August 04, 2013
Empty ROCLS spools on fantail
ROPOS and Seismometer

ROPOS was sent down to retrieve a seismometer at the end of VISIONS '13 Leg 3

Photo credit: NSF-OOI/UW/CSSF

Leg 3 of VISIONS ’13 is rapidly drawing to a close as we near the mouth of Yaquina Bay and the OSU dock at Newport, Oregon. The empty ROCLS spools tied down on the fantail of the Thompson as we make the transit are evidence of the successful cable installations during Leg 3. Those reels were full of bright orange cables when loaded on the ship. Now those cables are installed on the seafloor, part of the secondary infrastructure of the NSF OOI regional cabled ocean observatory.

The cruise update broadcast last night included a detailed wrap up of accomplishments on this leg. At the top of the list, the completed construction work: 14,000 meters of electro-optical cables and 1900 meters of electrical cables successfully laid in the caldera of Axial Seamount and at the base of the continental slope.  Other completed installations: two medium-power junction boxes, one bottom-pressure tilt instrument, one acoustic current meter, one seafloor pressure sensor, and two short-period seismometers that captured an earthquake in Axial’s caldera within the first hour of testing and data collection using ROPOS power and communications. Cables, connectors, instruments, and nodes were left in positions to be quickly connected to the RSN primary infrastructure whenever final acceptance is achieved.

The last completed ROPOS operation on Leg 3 was retrieval of a NSF Cascadia Initiative seismometer near the Blanco Fracture Zone.  This instrument had not responded to repeated acoustic commands that should have sent it rising to the surface for shipboard recovery. Instead, ROPOS went down and hooked in to the seismometer and carried it back to the Thompson. There was one more recalcitrant seismometer to rescue, at another location. Unfortunately, wind, waves, and a strong current combined to prevent a safe ROPOS launch and recovery before time ran out and the Thompson had to turn northeast for shore to return on schedule to Newport.

VISIONS '13 Leg 3 student participants presented their projects last night in the Library to a full house of science, engineering, and ship’s crew members. Topics ranged from 3D visualization of ROPOS dives to lab exercises comparing hydrothermal vent communities, from how scientists and engineers communicate across boundaries of cultural differences and vocabularies to ways of engaging more students and the public in ocean science. Many of the students have already posted blogs about their work here and final projects are being posted here.

Once in Newport, there will be a crew change, as many depart the ship after Leg 3, and other scientists, engineers, students, and ship’s crew get onboard for Leg 4, which is scheduled to set sail on August 6.

Contributed by Nancy Penrose, RSN Communications Coordinator