Seismologists monitor North Korea’s nuclear blasts

Dan Vergano | USA Today | May 29, 2009

A column about measuring the size of underground nuclear blasts by their seismic waves refers to a 1988 OTA report, “Seismic Verification of Nuclear Testing Treaties,” that suggested that it might be difficult to detect a nucleat test smaller than 5 kilotons.

In the two decades since that report, verification has improved and now smaller blasts can be detected, the article says.