Nuclear explosions can start or stop earthquakes.
FICTION: Scientists agree that even large nuclear explosions have little effect on seismicity outside the area of the blast itself. The largest underground thermonuclear tests conducted by the United States were detonated in Amchitka at the western end of the Aleutian Islands, and the largest of these was the 5 megaton test code-named Cannikin that occurred on November 6, 1971 that did not trigger any earthquakes in the seismically active Aleutian Islands. On January 19, 1968, a thermonuclear test, code-named Faultless, took place in central Nevada. The code-name turned out to be a poor choice because a fresh fault rupture some 4,000 feet long was produced. Seismograph records showed that the seismic waves produced by the fault movement were much less energetic than those produced directly by the nuclear explosion. Locally, there were some minor earthquakes surrounding the blasts that released small amounts of energy. Scientists looked at the rate of earthquake occurrence in northern California, not far from the test site, at the times of the tests and found nothing to connect the testing with earthquakes in the area.