Senator Alan Cranston of California wrote the forward for Larry L. Meyer's 1977 book, California Quake, which reported on the preparations for, and the attempts to develop a warning technology for, inevitable large quakes.
Cranston related his interest which stemmed, in part, from his early 1970's work on arms limitations and the nuclear test ban treaty. This required the ability to differentiate between bomb tests and earthquakes.
A Defense Department expert told Cranston that, with sufficient money and technology, they could tell the difference between nuclear tests and earthquakes. When pressed for details, the DoD expert's answer was simple: bombs don't give warnings.