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.
