A Chinese monitoring station, approximately 350 kilometers north of the test site, was the first to record the explosion. In seconds, its reverberations reached seismologists worldwide.
At this unassuming campus in Palisades, New York, Richards and Kim analyzed the data.
“The seismograph is a recording of how the ground moves at different times," said Richards. "The preliminary waves, or the primary waves, the first arriving waves, are very strong and impulsive. There are very weak waves in this part of the seismograph. You hardly see them at all here.”
“We know exactly where they carried out nuclear test, and the signals are very simple, just “boom,” compared with earthquakes cracking long fault," said Kim.
The seismologists point out that nuclear devices are usually tested in shallow caves, approximately 1,500 meters-deep. Earthquakes come many kilometers below the earth’s surface. The difference is easy to detect. In North Korea, according to Kim, they used the same area, but not the same site for their tests.
“In this case what we know that they had two tunnels drilled, two tunnels, one they call East, and the other West. And we believe this one is from the west side."
While the North Koreans celebrate their feat, Kim and Richards say that this latest test, even though small when compared to most American nuclear weapons, is very serious and that the device can do incredible damage if used as a weapon.
最新
2013-11-25
2013-11-25
2013-11-25
2013-11-25
2013-11-25
2013-11-25