The Langseth Galicia 3D seismic cruise is winding down. By tomorrow we will be back at the dock in Vigo. Like most seagoing science, we will
miss the ship experience, we will miss the new colleagues we have met, we will
look forward to getting back on shore, and for many of us the awesome
multi-year task of processing, interpreting, and publishing the boatload of data
we have acquired.
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| This is an example of the data we have collected. Right is to the East and left is to the West. This is a cross section of the Earth about 65 km long. The blue is water. The water depth here is about 5 km. The red and gray colors are a cross section of the rocks below the water. The flat layers are sedimentary rocks. The lumpy bumps (that is a technical term!) consist of blocks of continental crust and of the mantle. |
We thank the
Langseth’s Captain and crew for making this possible! These are men and women
who live on the sea, and who share their ocean world with us for a month or
two. Every now and then, when you can walk 100 meters in a straight line, ask
yourself, “Where is the Langseth now, and who is steering the ship, or keeping the
engines running, or keeping the deck ship-shape, or providing good food, or
every other important task on the ship?” Under your breath say thank you for
the experience you had on Langseth.
We thank Robert and his technical team. They worked
tirelessly to assemble the 24 km of hydrophone streamer that hears the
reflections from the Earth, the 40 or so airguns that make the booms, and all
the rigging it takes to tow them spread out behind the ship over 600 meters wide and 7000
meters long. That was just the start. Then they operated the electronic
equipment that received the seismic data and recorded it for the scientists.
Without them we could not do the science we love.
Thank you to the Science Party. We had a total of 20 scientists, including undergraduate students, graduate students, post-docs, researchers, and professors. On Leg 1 we had 14 scientists and on Leg 2 we had 10 scientists. Four scientists weathered both legs. Six joined us for Leg 2. I am very grateful for all your efforts on behalf of the Galicia 3D science. I hope that you learned a lot, had a good time, and met other scientists for the first time. I suspect that we will meet one another many times in the future.I look forward to that!
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| This is the Technical team and the Science team for Langseth Leg 2. |
I want to thank the Protected Species Observers for sailing
with us. They spent countless hours in the observing tower, high above any other
part of the ship. They have sighted hundreds of whales, but most did not come
close to the ship. It is windy and cold up there, but their role is important
for making sure that collecting our scientific data does not interfere with the
creatures who call the ocean home.
Thank you for sending your loved ones off on the Langseth. I
can certify that they now know how to do their own laundry and to clean up
their cabin before they leave the ship. During the weekly emergency drill, they
run quickly up to the muster station on deck and put on safety gear. I
recommend that you continue to enforce these behaviors ruthlessly! They will
forget them if you let them slack-off. On the other hand, they did not have to
cook their own food, or wash and dry their dishes. You will still have to work
on these behaviors!
As I write this from the Langseth, we should remember that
the Galicia 3D experiment goes on. Our colleagues from GEOMAR and University of
Southampton will be on the FS Poseidon from 25 August to 10 September. They
will be recovering the 78 Ocean Bottom Seismometers that are still on the
bottom (on purpose!). They have been recording approximately 150,000 airgun
array shots fired by the Langseth. I know what you are thinking. “How many
total recordings of shots are recorded in all the OBS’s?” That would be about
11.7 million shot recordings. This will keep the OBS scientists busy for a
while!
I particularly want to thank James Gibson for creating this
blog. It has reached out to our friends and to strangers. We plan to keep the
blog alive. This project will continue for years.
Best regards,
Dale Sawyer
Rice University
