A Multipurpose Scientific Outpost
The Yellowknife Geophysical Observatory is positioned on ancient Precambrian granite of the Canadian Shield, a location chosen for its geological stability and distance from the seismic noise of oceans and cities. This site's primary advantage is its placement directly under the Earth's auroral oval, the ring around the geomagnetic pole where the aurora borealis is most active. The facility is an important component of several national and international scientific networks.
Its longest-running experiment is seismic monitoring. Established in 1962, the Yellowknife seismic array (YKA) was created to detect distant underground nuclear explosions. It consists of 19 short-period seismometers arranged in a cross shape spanning 25 kilometers, supplemented by four broadband seismographs for detecting a wider range of frequencies. The station's data is transmitted in near real-time to the Comprehensive Nuclear-Test-Ban Treaty Organization's International Data Centre in Vienna. Alongside its seismic duties, the site has hosted a magnetic observatory since 1973 to continuously measure the Earth's magnetic field. This is accomplished with a Canadian Magnetic Observatory System (CANMOS) that includes a tri-axial ring-core fluxgate magnetometer and an Overhauser Proton Precession Magnetometer.