Logbook: August 28, 2006

Position: 45°56.65’N, 130°00.50’W

John Shanley and Haru Matsumoto (l-r) preparing the QuePhone for launch. View a movie (Quicktime format) of the launch. (click image for larger view)

The first thing we did when we arrived at Axial volcano was to deploy four ocean-bottom hydrophones (OBHs). These instruments are similar to seismometers in that they are designed to detect earthquakes, but they record sound waves instead of ground motion. The OBHs will monitor seismicity at the volcano for the next 1-2 years and then will be recovered.

Our second task was to recover the NeMO Net buoy that had been moored at the site for the last two years. But when we got to its location it was nowhere to be found! This was surprising because an MBARI ship had seen it here when they visited Axial just 3 weeks ago. Apparently, the buoy line had parted sometime in the last few weeks and we assume it is now adrift. We have put out a notice to mariners for other ships to keep an eye out for it, and hopefully it will be found. In the meantime, we plan to dive with ROPOS on the buoy anchor location to try to determine what happened.

Next, we deployed the MBARI autonomous underwater vehicle (AUV) for its first dive during this expedition. Everything seemed to be going OK during the first hour or so, but then the vehicle took an unexpected and unprogrammed turn and before we had time to react it was out of tracking range. Something had gone wrong, but we knew that the AUV would eventually float back to the surface and it had a radio beacon to help locate it. The ship started a systematic search pattern and eventually we found it! There was a lot of relief after the AUV was safely back on deck. Now the engineers will be diagnosing what went wrong with the vehicle’s navigation system.

Our next deployment was a QUEphone, a prototype instrument that is a combined float and hydrophone. Most hydrophones are fixed in one place and they have to be recovered to download their data, perhaps every year or two. The QUEphone on the other hand is designed to ascend up and dive down between the surface and the bottom at pre-programmed intervals, and it can send data back to shore via satellite each time it is at the surface. The hydrophone data can alert scientists to unusual earthquake activity or marine mammal vocalizations.