Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Great Progress Made by Seismologists in Identifying Violations of Nuclear Test Ban Treaty

23.10.2002


Advances in detection devices and methods of analysis have allowed seismologists to identify virtually all events that might be nuclear explosions of possible military significance under the Comprehensive Test Ban Treaty (CTBT), according to Prof. Lynn R. Sykes of Columbia University’s Lamont-Doherty Earth Observatory. Writing in the 29 October issue of Eos, published by the American Geophysical Union, Sykes analyzes 72 questionable events since 1960.



Verification was a major issue in the U.S. Senate debate in 1999, in which American ratification of the treaty was defeated. Since 1995, the International CTBT Organization has detected many small seismic events and has determined that many were earthquakes or otherwise identifiable. Under the treaty, however, the international organization is not charged with identifying all seismic events and is, in fact, not permitted to declare an event a nuclear explosion. Unresolved cases and possible nuclear events are referred to national CTBT agencies, whose work is usually classified.

Therefore, says Sykes, we do not always know how well the difficult cases are resolved. Only 72 events have been flagged in the literature or by the media as questionable or difficult to identify, a small fraction of all events recorded over the past 42 years, demonstrating the great progress made in verification, says Sykes. By studying technical characteristics of the seismic signals, nearly all of the 72 events have been identified as nuclear explosions, chemical explosions, earthquakes, or mine collapses, he writes.


Thirty years ago, problem events registered seismic magnitudes (mb) of 4.3 to 5.6, whereas today, most attention is focused on the mb 2.0 to 3.5 level. Since the magnitude scale is logarithmic, this represents an improvement factor of 300 in the size of signals that can be identified. It means that nuclear explosions 1,000 times smaller in their energy release can now be identified, says Sykes.

Since 1990, all of the problem events greater than mb 2.5 have received special study and have been identified. There is no evidence, says Sykes, that any countries have exploded nuclear devices since the CTBT was opened for signature in 1996, aside from India and Pakistan (which have not signed). Under the International Monitoring System, which began in 1995, seismic monitors have been placed close to, or in, countries that possess nuclear weapons, and the shorter the distance high frequency seismic signals have to travel, the better the identification of their source, Sykes writes.

Indian nuclear explosions on May 11, 1998, and Pakistani ones later that month were widely recorded and quickly identified. Sykes says the Indian claim of two tests with a combined yield of 0.6 kilotons on May 13, 1998, is surely exaggerated, as they created no detectable seismic signal. Similarly, media reports in 2001 of an Iraqi nuclear explosion in 1989 appear to be false, Sykes writes, as no seismic signal was produced.

Regarding suspected Russian tests on September 8 and 23, 1999, at Novaya Zemlya, Sykes concludes that, if they occurred at all, they were very tiny, that is, 0.001 to 0.02 kilotons. They may have been so-called "sub-critical" tests that release no nuclear energy, which are permitted by the treaty. Russia, China, and the United States have each conducted sub-critical tests since the treaty was signed in 1996. Sykes notes that to have military significance, tests must produce yields of at least five to 10 kilotons.

As for the future of verification, Sykes says that only on-site inspections can resolve any doubt in suspected events where the nuclear yield is zero, and this becomes possible once the CTBT enters into force. Short of that, occasional problem events may occur at the limits of detection. These will become fewer, as investigations of previous questionable events are published and the science of verification advances further, he concludes.

Contact: Harvey Leifert
(202) 777-7507
hleifert@agu.org

Harvey Leifert | AGU

More articles from Earth Sciences:

nachricht Climate change weakens Walker circulation
20.10.2017 | MARUM - Zentrum für Marine Umweltwissenschaften an der Universität Bremen

nachricht Shallow soils promote savannas in South America
20.10.2017 | Senckenberg Forschungsinstitut und Naturmuseen

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>