[Mike Fieschko]

This was the main reason, not earthquakes, that seismic stations where set up all over the place

Correct, and the USGS receives data from a seismic station located in Inchon.

[ruiner]

Umm, no. Actually three or four seismic stations setup across the US can pinpoint the location of a very large explosion or earthquake anywhere in the world.

The seismic waves travel throught the earth and are reveived at each station at different times. Since we can reasonable estimate travel times, each station can estimate a range of locations that the event occurred. The intersection of these location is the event spot.

Thus we could verify the USSR's compliance with non testing treaties from the US.