Revelle Blog #7 Seafloor stakeout

Dr. Claire McKinley is a Research Associate from the University of Washington. She is currently working and reporting on the research occurring along the Hikurangi subduction zone on board the US research vessel Revelle

Every aspect of the research we are doing, and all of the samples we are collecting are vital to our understanding of the subduction zone. An extremely unique portion of the research is our use of a remotely operated vehicle (ROV) called Jason.

ROV Jason moves from research ship to research ship all over the world with its crew from Woods Hole Oceanographic Institute (WHOI). ROV Jason is an engineering feat and can dive 6500 meters below the ocean surface and stay for week at a time.

ROV Jason has an impressive number of tools including two manipulator arms, eight cameras, a forward-facing sonar, two lasers that can be used to measure distances, and a “slurp” vacuum that can be used to take samples. Depending on the mission ROV Jason can also be set up with a multibeam system for mapping, a ban saw and many other tools.

When ROV Jason is in the water three people from the ROV Jason crew, a navigator, a pilot and an engineer operate the vehicle in 4 hour shifts to keep ROV Jason working 24 hours a day. It is operated from a furnished shipping van that is loaded onto the ship along with the vehicle and its own special winch.

The controls of ROV Jason flow through a fiberoptic cable that is woven into line that lowers Jason into the water. The van contains the computer that talks to the vehicle and has a wall of screens that show several camera perspectives as well as navigation and engineering information.

Three scientists also sit watch, one who leading the scientific objectives and two observing. One observer fills out the event log and the other takes video and still images. I have never felt more like I was on a stake out of as part of a spy organization before in my life. And spying on the seafloor is a lot of fun!

We use ROV Jason to look around the seafloor searching for signs of bubbles and the life associated with seeps. We are looking for seep areas because they bring fluid from deep within the subduction zone closer to the surface where we can sample it. 

We spend quite a bit of time taking ROV Jason to places that the mapping coring or heat flow measurements have shown there are seeps. This information guides us to the locations we will look at with ROV Jason to figure out where we put flow meters. 

The fluid flow meters are instruments that sit on the seafloor and collect pore fluid. These instruments will be retrieved in two years and will provide another crucial piece to the puzzle of slow-slip earthquakes and the tectonics of the Hikurangi subduction zone. 

These instruments will collect pore water over several years and we hope to figure out if fluid flow changes impact or respond to earthquakes, and we would not be able to deploy them without ROV Jason. So far, ROV Jason has collected lots of sediment samples, heat flow measurements, and later this week ROV Jason will collect the first year of data from the earthquake observatories buried 450 meters before the seafloor.

It is a unique and moving experience to view the seafloor in such a detailed and in-depth way. Usually the extent of the seafloor I get to see is the material that comes up in the core. It is very different to be able to see the entire sea floor, and all of the life that is under water, to really know where the sediment and pore water we collect comes from.

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