Logbook: August 28, 2003

45° 51.8' N, 130° 00.2' W
Air temperature 60° F, 1500 PST

Science Report

At 1000 PST the Thompson arrived at Axial caldera. The first task was to deploy the Ocean Bottom Hydrophone (OBH) over the side of the ship. Next the ship steamed south 8 kilometers to the Southern Pillow Mound area, where ROPOS was deployed for its first NeMO 2003 dive. The main task of dive R734 will be to make 3 transects from the Southern Pillow Mound area to the center of the caldera, taking pressure sensor readings at 5 benchmarks on each transect. The purpose of the measurements is to see whether or not the volcano is inflating with magma and building up to its next eruption.

Left to right: Frank Spetla, Jon Shanley, and Terence Singerline prepare to deploy the Ocean Bottom Hydrophone (OBH). The hydrophone is the white cylinder in the foreground. .

Teacher's Report
Bill Hanshumaker, Educator at Sea

The morning dawned clear and calm, after steaming overnight through choppy seas. Following breakfast we had a brief science team meeting to update the deployment and recovery schedule. The first device deployed was an Ocean Bottom Hydrophone (OBH). It is secured to a weight in approximately 1500 meters of water. The OBH is used to listen to the sounds of underwater volcanoes and earthquakes. It will be collecting data over the next two weeks and we will recover it before returning to shore. To recover the OBH, scientists on the Thompson send down an acoustic signal that triggers the weight's release from the instrument package. Once released from the weight, glass floats protected by yellow "hard-hats" raise the OBH to the surface for recovery. Technicians and researchers were actively preparing the ROPOS for its first dive. Antifreeze and other fluids were added to help protect the hydraulics and electrical systems from the pressure of the ocean bottom.

Gitai Yahel, studying at University of Victoria, attaches bottles to the suction sampler before the first ROPOS dive. .

Researchers added collection bottles to the suction sampler, enabling multiple samples to be collected without returning to the surface. Equipment failure could result in missed opportunities for data collection and new discoveries. ROPOS was deployed at 1300 hours for a descent to 1700 meters. It is scheduled to be submerged for approximately 40 hours.

My ship board training continues. I am scheduled to stand watch from 2000 to 2400, but will be assisting in the control room during the entire dive. My primary responsibilities include tracking and logging the videos captured by ROPOS. It is only through the completion of meticulous records that the physical environment can be correlated to the collection activities and specific samples. I will be sitting in a dark room looking at numerous monitors, simultaneously logging several videos. This wasn't exactly in my image of being "at sea".