In the 1960s, the Department of Mines and Technical Surveys (now Natural Resources Canada) participated in a unique experiment with the United Kingdom Atomic Energy Authority to test the capabilities of a proposed seismometer array to monitor underground nuclear weapons tests.
Each array consisted of two lines of seismometers stretching 10–25 kilometres in the shape of a cross, T, or L. It was proposed that these arrays could be focused to record the seismic waves from underground tests originating from specific locations on Earth. Another hypothesis suggested that smaller 1–2 km clusters of seismometers might be more effective.
The Canadian array and cluster were constructed in wilderness underlain by stable bedrock west of Yellowknife, Northwest Territories. In time, research showed that arrays performed better than clusters at monitoring underground nuclear explosions. The cluster method was abandoned, with arrays becoming the preferred monitoring tool.
Now, more than half a century later, the Geological Survey of Canada’s Yellowknife array continues to monitor for nuclear explosions as part of the International Monitoring System of the Comprehensive Nuclear Test-Ban Treaty. Vestiges still remain, however, of the original early experiments, including this wooden vault that once housed a cluster seismometer.
Category: Equipment and Instrumentation
Manchee, E.B. and Somers, H., 1966. The Yellowknife Seismological Array; Publications of the Dominion Observatory, v. 322, p. 69–84.
Burch, R., 1968. An Examination of Cluster Recordings from EKA and YKA Relative to a Single Seismometer; Atomic Weapons Establishment Blacknest Note AG/84, 11 p.