The National Facility for Seismological Investigations (NFSI) held a marine seismology workshop at Dalhousie University, Halifax, Nova Scotia. This weeklong course aimed to provide technical training for both graduate students and early career in marine seismology. Trainees came from across Canada and internationally to attend the workshop. The evening before the workshop officially began was an ice breaker event where all attendees were able to mingle, reconnect with old colleagues and make new connections over delicious pizza and drinks. The first two days consisted of lectures covering the fundamentals of seismic waves and Earth structure (Q. Liu & Y. Liu); passive and controlled source seismology methods (A. Frederiksen & F. Darbyshire & K. Welford); data acquisition (A. Schaeffer); and practical considerations on the use of ocean bottom seismometers (G. Cairns & M. Nedimovic). Both days had a keynote lecture from one of the invited speakers Juan Pablo Canales and Helen Janiszewski. Prof. Canales discussed various controlled source seismology expeditions he has led to understand near surface structures and tectonics in oceanic crust boundaries. Prof. Janiszewski presented on a comprehensive study of global noise characteristics collected by ocean bottom seismometers and methods to remove this noise.
A tour of the NFSI facility was held where participants had the opportunity to see up close some of NFSI’s fleet of ocean bottom seismometers, a newer design called the Aquarius. Various features of the Aquarius were discussed as well as current developments to improve the design. The other equipment, such as the computer that interfaces with the Aquarius, devices for locating them on the ocean floor (e.g. omnidirectional dunker) and the battery charger unit were discussed. During the tour, a short lecture (K. Bosman & J. Thibodeau) was given on the timetables for ocean bottom seismometer deployment and recovery which can take several hours for a single instrument.
After the first two days, attendees were split into four groups evenly divided by students, early careers and mentors. Each group separately took part in a field trip to the New Harbour docks for a short cruise on the boat, Island Venture 1, to observe an Aquarius being deployed and recovered. The work of dropping the seismometer into the water, catching it and reeling it in was done by the vessel’s skilled skipper and deckhands. Attendees that had proper footwear were able to don hard hats and participate in the safer parts of the deployment and recovery, trying out the software to communicate with the seismometer on the sea floor and reapplying the burn wire and other fittings after it had been recovered.
Another day of the workshop was spent in the computer lab, learning to work with software for ocean bottom seismology. All attendees got hands on experience running software to remove noise from seismic data (P. Audet), such as was discussed in Helen Janiszewski’s presentation and software for detecting and locating earthquake events with ocean bottom seismometers using machine learning (M. Zhang).
On the final day of the workshop, the four groups split up again and were tasked with creating a proposal for an ocean bottom seismology experiment. The lectures of the previous days gave trainees the relevant information about how to plan such an experiment. A budget of 2 million dollars was given and not only the cost of the devices themselves but also ship time also had to be taken into consideration. Group mentors guided the students in the experiment design. Each group drafted a proposal and gave a presentation to the entire workshop about their study. The western Aleutian Islands, the coast of Brazil, the Indian Ocean and the Laurentian Fan were proposed study areas. The day culminated in a reception dinner where the winners of the best proposal were announced, judged by the two keynote speakers.
Post workshop, some trainees stayed an additional day at the NFSI facility to get more hands-on training with the software and equipment needed to deploy an Aquarius ocean bottom seismometer.
Overall, the workshop was a great experience to learn more about ocean bottom seismology from different perspectives, to develop critical thinking and teamwork skills, and to network with people across a wide variety of career stages.
