11 November, 1995

November 11, 1995

Location: On Transit to the Southwest Scotia Sea
Starting point for Sea Beaming 60 11" South Latitude x 56 12' West Longitude

Update: We finished another successful drift along a ridge near King George Island early this morning using the ZAPS Sled. All the scientists were excited about the results. The OSU team will take a couple of days to analyze and organize their data b efore we return to the area to try and more closely pinpoint the location of the hydrothermal vents that we suspect are in the area from the water chemistry data that has been collected.

We are heading to the Southwest Scotia Sea to do sonar mapping and seismic mapping of the sea floor to gather data about the influence of three small micro tectonic plates which are converging in this area. The precise location of these plates is not known. It is hoped that by our mapping we can identify the convergence area. From this location data the Texas team would like to do seismic work along the convergence to determine the rate of motion of the plates in this area and to determine in what d irection they are moving relative to one another.

This means that we will be traversing hundreds of miles of the Scotia Sea in the southern Drake Passage. We will be following a route that follows a direct course for about twenty miles then we will make a slow 180 degree turn that brings us in the op posite direction along that original course. On each twenty mile transit, we will be producing a map of the sea floor. When we make the 180 degree turn, the ship will be a distance of about three miles from the center line of the map produced on the pre vious transit. By following this serpentine route, the scientists are able to collect data of the sea floor which allows them to produce a continuous map of the topography of the sea floor.

This is a long and time consuming process. We move at a constant speed of 10 knots through what ever seas the Drake throws our way. Since we are constantly changing our course, the motion of the ship is constantly changing. We roll from port to star board for an hour or so then we pitch from aft to stern. It is hard for many of us to adjust to the changing motion. By midnight, the usually busy dry lab where the Sea Beam equipment is kept was quiet except for those of us on watch. Very few people s howed up for midnight meal, usually a meeting time for most of the science staff and support crew each night in the mess hall. Tonight, people found retreat in their bunks. Many of us took medication to help with sea sickness. All of us feel the change in motion to a greater or lesser degree. I notice that during these rough seas that everyone is a bit sluggish. It takes just a little longer to get things done, and it is much harder to concentrate.

On days like today you really start to focus on how powerful the sea is. We all know that our rough ride is a necessary evil of doing research in this area. We look forward to some calm seas back in the Bransfield Strait when we continue our hydrothermal research.

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