ABSTRACT
By the middle of 1987, the Natural Resources Defense Council's (NRDC) seismic verification project was in a curious stage of development. American scientists had already spent a year in residence at seismic monitoring stations in Kazakhstan, and the NRDC had built virtually identical stations in California and Nevada to monitor nuclear explosions at the Nevada Test Site. Although NRDC's operation of the stations in the United States was unrestricted, so that these stations could provide continuous monitoring of test site activity, the Soviets required the Kazakhstan stations to be shut down during Soviet nuclear tests. Despite the distances and the low yield of the explosion, all of the NRDC stations detected the explosion, and its waves were clearly distinguishable from those caused by a distant earthquake which occurred, coincidentally, at almost the same moment as the test explosion.
