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RRU researcher heads into uncharted waters

August 15, 2011
By: 
Amy Dove

B.C.'s earthquake history is muddy, literally.

Deciphering that mud and establishing patterns for coastline seismic activity is one reason Audrey Dallimore goes to sea. The Royal Roads University professor does so armed with high-tech equipment to read sediment cores.

Her work is evolving with help from a Geotek Multi-Sensor Core Logger (MSCL). To be shared with other researchers, it is the only one of its kind on the West Coast. It was funded by grants through Royal Roads from the Canada Foundation for Innovation and the BC Knowledge Development Fund.

Work that used to take Dallimore months will now be recorded in hours in line with international geologic standards. That information includes water column properties, nutrient and mineral levels and occurrences of earthquakes.

"We can actually reconstruct what the environment would have been through time," she says.

Dallimore, and a team from Canadian Coast Guard, Natural Resources Canada and other scientists, are conducting a nine-day research cruise in Barkley Sound on the CCGS Vector. Designed as a research vessel, the Vector is a Lego ship with movable winches and cranes screwed to the deck to suit project needs. On Aug. 13, Dallimore and the team will have six hours to load up the ship before embarking on the cruise.

The timing is opportune as they can measure the impacts of the March 11 tsunami in Japan on the B.C. coastline while testing the equipment. Knowing the impact on sediment here could provide insight into past disturbances.

"We need to have regional records to find the big earthquakes," she says. "That helps us to interpret how the subduction zone is working. We live in a tectonically active area and there are a lot of issues we need to understand."

The team capitalizes on daylight hours to lower equipment over the side of the boat, bringing up sediment cores and other samples. At night, operations switch to "mowing the lawn," Dallimore says. Using sonar and other technology, they map the ocean floor. 

"You use every moment of ship time that you can," she says, noting the vessel costs $12,000 a day, covered by an Natural Science and Engineering Research Council grant.

The data collected will keep scientists busy for six to 12 months. The new equipment allows them to use ship time and lab time more efficiently, ultimately allowing that information to be shared with other scientists sooner, Dallimore says.

Barkley Sound is the ideal place to test out the multi-sensor for several reasons. There is a 15-year data record of conditions in that location, something that doesn't exist for most of the coastline. Located in Pacific Rim National Park, the area has wilderness but is still accessible. It is open to the Pacific Ocean, but protected enough for small boats and there is a rich archaeological history there.

"It's a wonderful area for training students," she says.

From there, the team hopes to expand out to more remote areas of the coastline. Previous research trips have had to focus on three locations on the B.C. coast where "laminated sediment cores" could be located. These cores come from areas where there is no life or extreme water movement to disturb the sediment. The layers are so intact the naked eye can make out lines denoting years, Dallimore says.

Now, with the multi-sensor, Dallimore can scan a laminated sediment core, calibrate her equipment off it and compare that to the more common "blind cores" which come from areas where the sediment layers are disturbed.

The ability to analyze "blind cores" will allow the team to build up a database of earthquake activity for B.C's entire coastline. It is hoped that Dallimore's work will provide insight into how often, and to what severity, earthquakes have rocked the coastline historically.

It's not just the multi-sensor that is opening up the ocean floor to Dallimore. Included in the grant package was funding for a Lab in a Trailer (LIT). It's essentially a mini oceanographic research lab, Dallimore says. The equipment can take lightweight sediment cores, analyze properties of the water column and other research tasks, and should be ready next summer.

The trailer will then be hitched to a vehicle, driven to the desired location and the equipment loaded onto a 20-foot boat. That boat can access the near shore, allowing researchers to fill in data gaps left by trips on the larger Coast Guard vessels. The near shore accounts for everything within 50 metres of the tide line. That area is rich in information, harbouring archaeological sites and nutrient rich sediment, Dallimore says.

"We can actually see how human communities are impacted by natural cycles," she says. The data Dallimore collects, when combined with archeological information can define changes in sea and climate conditions and its impacts to human diet for example.

"We are hoping in the fullness of time that we might be able to train small communities and First Nations bands to do basic monitoring of their near shore environment," she says. That information provides a really rich story that can have positive impacts on city and sustainable community planning through building codes, she adds.

The cruise is strongly supported by the collaboration of organizations involved, Dallimore says, noting there will be eight scientists and 12 Coast Guard staff on board. She is proud that a grant given to Royal Roads University can be leveraged to create collaborations with scientists from Natural Resources Canada, and other western Canadian Universities.

The Geotek Multi-Sensor Core Logger

THe MSCL was designed to conduct non-destructive testing on mud and rocks, says Peter Schultheiss, Geotek managing director based in England. He was in Victoria prior to the research cruise to ensure the equipment was ready to go.

"It provides you with a lot of detail before you decide what else you want to do with the core," he says.

The machine can take detailed information on sediment or rock cores, making it a valuable tool for researchers and industry such as mining, Schulteiss says.