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SOMBA K'E/YELLOWKNIFE
It may not be earth-shattering news, but Yellowknife residents might be interested to learn that a federal seismic monitoring station northwest of the Yellowknife Golf Club is recording its 50th anniversary this year.

Established in 1962 by the British Ministry of Defence and the Canadian Defence Research Board, the sensitive equipment at the station picks up signs of natural and man-made seismic disruptions. The location was picked, according to station workers, because of the naturally low level of underground noise in the region and its distance from oceans, urban areas and major highways, which can be bad for detectors.

Seismic technologist Ross Ashlie led Yellowknifer on a tour through the Natural Resources Canada site last week to mark the anniversary and to get a sense of what happens at the facility.

The station includes a dome-like building staffed by three full-time employees, which serves as a command centre for an entire seismic array, including 18 short-period and four broadband recording sites.

Powered by propane, each of the sites includes a seismometer, which picks up ground movements and a digitizer that turns the ground activity information into 1s and 0s to then broadcast a signal back to the command centre. That information is then sent on to scientists in Ottawa and Vienna's International Monitoring System - the central location for seismic stations all over the world. It is there an origin for an earthquake or man-made explosion can be found with all of that data.

"If any man-made or natural event happens anywhere on Earth, basically it will arrive at each one of those (seismometers) on a separate, very slight difference in time and they can help triangulate where it originated from and whether it is actually a natural or man-made event," said Ashlie.

Each of the local sites are about two-and-a-half kilometres apart and are configured in a north-south and east-west line. A 250-square-metre "scientific reserve" is blocked off where the sensors are located and no development can take place in that area without federal authority.

Because of the sensitivity of the equipment, unrelated movement underground such as excessive traffic movement or construction blasting can disrupt the data.

Ashlie said that in the early 1970s one seismic site had to be removed entirely because of urban noise from the growth of Yellowknife and gold mining at Giant Mine.

Generally, if a major earthquake takes place somewhere on the planet, the station will detect it, but it isn't something Ashlie notices because the data constantly runs in real time from the seismometers through the station's computer equipment to Ottawa to Vienna.

"Often we don't see the data," he said of his role as a technologist." We don't usually monitor it because we aren't the seismologists. We just keep all the equipment going."

Ashlie, who is an electronic technician by trade, is responsible for accessing the seismometers year-round generally with a snowmobile, Argus or Foremost Nodwell all-terrain vehicle to conduct maintenance and refuel the detection equipment with propane. Around March or April, he goes out with a partner in a Nodwell all-terrain vehicle over a two-week period and fuels the devices for a full year.

The job also requires a lot of maintenance. Over the past three years since working at the station, Ashlie said he has run into problems with vandalism and theft of equipment on the sites, largely because most sites are near active snowmobile trails.

"This array is really important for the safety of everyone and very important for nuclear testing," he said, noting that when foreign countries can test nuclear weapons under the ground, it is a national concern. "When you have places like Iran and North Korea making threats, you hate to see the stuff vandalized and stolen out there."

Ashlie said the observatory has had one of their on-site $6,000 thermoelectric generators stolen, which was especially annoying. The generators burn the propane and produce about 20 watts of power for the equipment.

"We can't really see any use for it for anyone," he said. "It is an inefficient way of producing electricity for general use. If someone stole it for their cabin, they are going to quickly find out that it is kind of useless for them. It won't even power half a light bulb."

The propane tanks on the sites are also been kept insulated with wooden boxes close to the ground so that the fuel can stay warm enough to keep the equipment running all year long.

"We have had people ripping open the boxes and taking the insulation out to sit on while they sit and have a bonfire to roast their weenies," he said of incidents that he has seen.

Ashlie notes that the facility is in the process of making the seismic sites solar-powered by the fall, so that the locations will only use propane for backup.

"We are anticipating the sites will run year-round on solar power even in December when light is at the very minimum," he said.

Ashlie said he enjoys being able to tinker with the equipment and drive the all-terrain vehicles, which "go anywhere in the bush."

"What I love about my job is that it is outdoors and indoors," he said. "The job isn't for everyone. The bugs can get pretty bad."

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