Student Seagoing Experiences: The 2013 Cascadia Initiative Expedition Team’s Apply to Sail Program

Compiled by Emilie Hooft (University of Oregon) for the Cascadia Initiative Expedition Team

During the summer of 2013 the Cascadia Initiative Expedition Team led six oceanographic expeditions to recover and redeploy ocean bottom seismometers (OBSs) across the Cascadia subduction zone and Juan de Fuca plate. The Cascadia Initiative (CI) is an onshore/offshore seismic and geodetic experiment to study questions ranging from megathrust earthquakes to volcanic arc structure to the formation, deformation and hydration of the Juan de Fuca and Gorda plates with the overarching goal of understanding the entire subduction zone system. These objectives are all components of understanding the overall subduction zone system and require an array that provides high quality data, crosses the shoreline and encompasses relevant plate boundaries. The CI is the first to utilize a new generation of OBSs that are designed to withstand trawling by fisheries, thus allowing the collection of seismic data in the shallow water that overlies much of the Cascadia megathrust.

Figure 1. Cascadia Initiative experiment design: PBO GPS stations upgraded as part of the Cascadia Initiative (black triangles) and broadband seismometers (circles) expected to operate in the Cascadia Region between 2011 and 2015. The 2010 workshop report1 contains a detailed discussion of the color-coded seismometer experiments and the schedule of deployments.

Figure 2. Robert Anthony (New Mexico Institute of Mining & Technology) counts how many SIO Abalone remain to be deployed.

We all gathered on the deck as the persistent thumping of the Oceanus’s V16 diesel died away and the slow lapping of waves against the stern took its place. Our GPS indicating that we were in the correct spot, the crew began operating the crane to raise the oven-sized Ocean Bottom Seismometer (OBS) over the starboard side. For a second, the florescent yellow casing on the instrument was picked up by the ship’s floodlights, illuminating the instrument package against the dark, endless expanse of the Pacific Ocean. Then, just as quickly, it was released from its tether and engulfed by the swell. I leaned overboard and watched as the blinking light affixed to the top of the instrument silently faded away, eclipsed by the murky depths of the sea. Turning my back on this makeshift funeral, I imagined the OBS settling on the alien terrain of the ocean floor, perhaps on a turbidite flow. As the ship’s diesel fired back to life and set course for the next drop off location, I thought about the OBS one day disengaging from its anchor and rising back up through the water column, possibly carrying with it the key to predicting crucial properties of the next submarine landslide-triggering earthquake.Robert Anthony, Graduate Student at New Mexico Institute of Mining and Technology

The CI is a plate-scale experiment that provides a unique opportunity to study the structure and dynamics of an entire oceanic plate, from its birth at a spreading center to its subduction beneath a continental plate. Together with the land stations that are part of the amphibious array and other land networks, the OBSs will provide coverage at a density comparable to the Transportable Array of Earthscope from the volcanic arc out to the Pacific-Juan de Fuca spreading center segments.

I was a member of the first leg of the 2013 CIET cruises. I was extremely nervous about every aspect of the cruise, including the bunk rooms and food. The first few days were great. I learned about ocean bottom seismometer retrievals and a bit about each of the crew members. Then we started experiencing high winds and seas. I had stopped taking my seasickness medicine, so I spent most of the time in my bunk. During the last four days of the cruise, I helped with retrieving and securing the seismometers. I spent a lot of time talking with the crew from Woods Hole Oceanographic Institute. I also learned that the entire crew has a special skill to do what they do, especially with significant weather. Even though a few days were terrible for me, I will gladly join a scientific cruise again, as long as I don’t forget my seasickness pills.Hannah Mejia, Graduate Student at California State Polytechnic University, Pomona

Figure 3. The WHOI team recovering an OBS.

The CI is a community experiment that provides open access to all data via the IRIS Data Management Center, thus ensuring that the scientific return from the investment of resources is maximized. The Cascadia Initiative Expedition Team (CIET) is a group of scientists who are leading the seagoing expeditions to deploy and recover OBSs and the team just completed its third year of data acquisition. The CIET maintains a website for the community where information regarding CI expeditions and OBS metadata are provided.

Having sat through several planning meetings and teleconferences in which the community hashed out where exactly the ARRA Cascadia Initiative OBS units would be deployed, it was a real pleasure to actually participate in the CI Leg 5 deployment cruise. Prior to the cruise, OBSs were a bit of a mystery, and it was fascinating to see their various parts and pieces and well-engineered simplicity. Some of the pieces were familiar, such as the Trillium Compact seismometer, although its casing that houses a 360-degree gimbal was new; others were completely foreign, most notably “syntatic foam” which doesn’t significantly compress even at 6000 m, or 200 bar pressure. It never occurred to me that one can’t use any old flotation foam, nor that fishing trawler resistance is a key design criteria of OBSs in general, and particularly offshore the Cascadia margin.Tim Melbourne, Professor at Central Washington University

The CI also includes a significant education and outreach component that is providing berths for students, post-docs and other scientists to participate in either deployment or recovery legs, thus providing the seismological community with opportunities to gain valuable experience in planning and carrying out an OBS experiment. In total, 51 applicants from the US and 4 other countries applied to sail on the 2013 cruises; 21 graduate students as well as a few undergraduate students, postdocs and young scientists from the US and Canada were chosen to join the crew.

Figure 4. Tim Melbourne (Central Washington University) explains the GPS component of the Cascadia Initiative during an onboard science meeting.

My time on the R/V Atlantis showed me first hand that the geology of the sea floor is just as interesting and diverse as the geology on land. One of the most memorable things to me was our use of the bathymetry equipment to scan Hydrate Ridge, which is a formation composed of methane hydrate – a flammable substance that looks like ice. It is amazing to think that every time we sent the JASON ROV down to collect a seismometer, its cameras were looking at a part of the sea floor that had never been looked at before. This really drove home the idea that some things that we take for granted when working on land, such as orientation of the seismometer during installation and the ability to look carefully at the rock and sediment that it is installed on, are much more difficult to achieve when working at sea – it really does present a completely different set of challenges.Anton Ypma, Graduate student at Western Washington University

Sailing on the R/V Atlantis was an amazing opportunity to learn more about ocean seismology and ocean-bottom seismometers (OBS). I had little experience with in situ seismic observations and instrumentation prior to the cruise. I learned a tremendous amount about how the OBS detects movements in the Earth’s crust, the advantages of the different encasing designs (e.g. trawl resistant mounts (TRM), pop-ups & float – ups), and the recovery process for each design structure. I appreciate the folks from Lamont-Doherty Earth Observatory who answered my many questions regarding OBS’s and allowed me to get a hands-on experience helping them break down the TRM’s after recovery.Katie Kirk, Graduate Student at Cornell University and Woods Hole Oceanographic Institution

Having never done field work in seismology, what stood out most from this cruise was the incredible design and engineering that went into collecting this data. Seeing a team of scientists and engineers coordinating with the crew of a ship, I felt struck by the reality of what science in action looks like, and what can be accomplished through collaboration. I didn’t know what to expect from ship life, but to sum it up concisely: The motion of the ocean stops for no stomach. The motion of the ocean is also soothing, and often sleep-inducing after lunch, so plan accordingly. The ship is well-stocked with books, movies, games, and characters to enjoy them with. The food is very, very good. And there is nothing quite like the crashing of waves against the hull as you watch moonlit clouds float by over a landless skyline.Laura Fattaruso, University of Massachusetts Amherst

The cruises lasted from 6 to 14 days in length. OBS retrievals comprised the three first legs, of which the first two were aboard the Research Vessel Oceanus. The third retrieval leg was aboard the Research Vessel Atlantis and utilized the submersible Remotely Operated Vehicle (ROV) Jason. The ROV was used to recover 12 of the 30 seismometers for this last retrieval mission. The final three legs were OBS deployments conducted with the assistance of the Research Vessel Oceanus.

Figure 6. AB Doug Beck helps Brooklyn Gose (Undergraduate at University of Oregon) with an albacore tuna

Figure 5. Samantha Bruce (Adjunct Instructor at College of Charleston) holding a starfish in front of ROV Jason.

I woke up and immediately realized that the boat was unusually still. Even though it was nearly 11 o’clock in the morning, I felt groggy. I had volunteered for the night shift and we had only been at sea for a few days so my body wasn’t fully adjusted to the new schedule. I got dressed and made my way to the top of the steps leading to the science lab. The WHOI team had their hardhats and life vests on and were darting into the lab and back out onto the deck-clearly hard at work. We were stopped because during the last deployment one of the ARRA OBSs had failed to respond when pinged almost as soon as it was released into the water. A similar situation had happened to us the day before with the ARRA ceasing to respond about halfway through its descent. With the recent failure, there was now a major dilemma. Of the three ARRAs deployed, two were not responding. The WHOI team was busy testing the remaining OBSs by submerging them, pinging and waiting to hear a response. The chief scientists spent the day pouring over maps, sending emails and developing plans for the worst case scenario. As the day progressed, we were still no closer to understanding the problem. It was decided that the ARRA component designed to send and receive signals needed to be tested at depth. The WHOI team gutted the cage holding all the CTD equipment and attached the ARRA parts. Each ARRA was tested and each ARRA continued to function normally. By now we had an updated itinerary that paired priority sites with the KECK OBSs that seemed more stable. The cruise continued with the stipulation that if one more ARRA failed then they would no longer be deployed. It made the next few sites extremely intense, but as the days went by without incident the anxiety began to lift. In the end, the two ARRAs that failed at the beginning of our voyage were the only two to do so and we still finished ahead of schedule.Miles Bodmer, Graduate Student at University of Oregon

It took landing in the middle of the craton in Indiana at the beginning of undergrad to make me realize that I have always wanted to live and work near the ocean. My time on the R/V Oceanus was the first opportunity to spend multiple days at sea, working on a small subset of a large scientific initiative. It seemed that every time I rolled out of bed, bleary-eyed and unaware whether it was night or day, something new was happening on deck. Fishing for tuna on hand-lines tied to the back of the boat, watching a pod of orca whales gambol around our boat or playing with a makeshift cornhole set, there was always something new to see. The engineers were great, and I overheard them explaining each remarkable mechanism making up their OBS design with enthusiasm and pride. After a couple of days I was nipping into the galley for a midnight snack or popping up to the bridge with the feeling of being one of the crew, part of the ship, necessary. Though this ship will drop us off and its crew will depart again within the week leaving us to return to our mainland institutions, I am sure this will not be my last voyage.Kasey Aderhold, Graduate Student at Boston University

Figure 7. Two young orcas playing.

More descriptions and pictures of individual at-sea experiences are on the CIET Website. The 21 Apply-to-Sail participants for 2013 listed in the order of cruise participation are: Hannah Mejia, California State Polytechnic University Pomona; Sara Kowalke, University of Minnesota; Stanislav Edel, New Mexico Institute of Mining and Technology; Laura Fattaruso, University of Massachusetts Amherst; Lexine Black, California State University, Northridge; Anton Ypma, Western Washington University; Samantha Bruce, College of Charleston; Katie Kirk, Cornell University & Woods Hole Oceanographic Institution; Christina King, University of Rhode Island; Ye Tian, University of Colorado at Boulder; Miles Bodmer, University of New Mexico; Robert Skoumal, Miami University; Kasey Aderhold, Boston University; Robert Anthony, New Mexico Institute of Mining and Technology; Shannon Phillips, University of Oregon; Tim Melbourne, Central Washington University; Brooklyn Gose, University of Oregon; Xiaowei Chen, Woods Hole Oceanographic Institution; Yajing Liu, McGill University; Harmony Colella, Miami University of Ohio; Martin Pratt, Washington University in St. Louis. ■

“Report from the Field” was designed to inform the community of real-time, exciting GeoPRISMS -related research. Through this report, the authors expose the excitement, trials, and opportunities to conduct fieldwork, as well as the challenges they may have experienced by deploying research activities in unique geological settings. If you would like to contribute to this series and share your experience on the field, please contact the GeoPRISMS Office at info@geoprisms.nineplanetsllc.com. This opportunity is open to anyone engaged in GeoPRISMS research, from senior researchers to undergraduate students.
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Reference information

Student Seagoing Experiences: The 2013 Cascadia Initiative Expedition Team’s Apply to Sail Program , Hooft E. for the Cascadia Initiative Expedition Team

GeoPRISMS Newsletter, Issue No. 31, Fall 2013. Retrieved from http://geoprisms.nineplanetsllc.com