Mohan,
Regarding use of seismic data to detect nuclear tests.
India appears to have deliberately conducted Monday's three tests simultaneously, in order to make it difficult for outside observers to make separate estimates of the explosive yields of the three tests.
There is no hard and fast formula that can be used to equate seismic measurements (on the Richter scale) to TNT equivalent. The relationship can vary depending on the nature of the geology in the test location.
For example, since we conducted so many underground tests in Nevada, the U.S. has plenty of data that could be used to estimate the yield of any future underground test in Nevada using seismic readings alone.
But all we have for calibrating India's latest test is the data that was taken from their 1974 test.
The Indians would certainly be aware that outside observers would be using seismic data to estimate the explosive yield(s).
Regarding the claim by Dr. van der Vink that India is exaggerating the yield of its test Monday. I think that this is possible. But it's also possible that the Western scientists are wrong. Only the Indian scientists know for sure if they are telling the truth.
The Indians surely have local seismic data, while the nearest seismic data used by the West was taken 435 miles away. India is now faced with some very difficult decisions about how much information to disclose about the test. In order to rebut charges of exaggerating the yield, they might choose to publish their scientific data.
It will also be interesting to see if they release information about the design of the thermonuclear device, or give any details about how long the development project took, etc.
There should be no doubt that Pakistan would find it impossible to develop a full-scale thermonuclear device. Further, one risk the Pakistanis face in detonating whatever device they now have is the possibility of it being a fizzle or a dud. If a nuclear test were conducted in complete secrecy and it proved a dud, then nobody would know. However, given all the world's attention on Pakistan now, it would be impossible for a test to be conducted in secret.
David |
