Scientific conference assesses CTBT verification capabilities

“This project is about connecting to the scientific community around the world so that we can learn from each other, enrich and inspire each other.” Welcoming participants to the three-day long International Scientific Studies (ISS) Conference in Vienna, Austria, on 10 June 2009, the ISS project chairperson, Ola Dahlman, explained that the purpose of the project was twofold: to assess the capability and readiness of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) verification system; and to further develop the cooperation between the scientific community and the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO).

The Conference was the culmination of a year-long series of independent assessments and studies of the CTBT’s ability to detect nuclear explosions anywhere on the planet. There were roughly 600 participants from around 100 countries, including approximately 500 scientists, who came together to contribute ideas, data and research findings. Over 200 scientific posters were submitted to the Conference covering the eight topic areas addressed by the project. The number of participants and diversity of countries represented reflected the interest that the project has generated worldwide. The United Nations Secretary-General, Ban Ki-moon, addressed participants through a welcoming video message. The Conference was then officially opened by the Austrian Foreign Minister, Michael Spindelegger (), and Tibor Toth, the Executive Secretary of the CTBTO ( address ). Please click here for information about the opening ceremony.

The Conference involved a series of presentations and panel discussions in which some of the world’s most eminent scientists in the verification field participated.  Various themes were discussed in detail including:
•    Advances in the detection capabilities of the four CTBT verification technologies over the last decade.
•    Synergies between the different technologies.
•    On-site inspections.
•    Potential civil and scientific applications of verification data.
•    Science for security.
•    Future collaboration between the CTBTO and the scientific community.

The CTBT’s International Monitoring System (IMS) was described by scientists as unique in terms of its technical equipment and global coverage – by the time the Treaty enters into force, there will be 337 monitoring facilities around the world.

Scientists across the board praised the high quality, accuracy and reliability of monitoring data and analyses provided by the CTBTO.  Dmitry A. Storchak of the International Seismic Centre attributed this to the consistency in procedure and the high standard of technologies and instruments used.  Paul G. Richards of the Columbia University, USA, added that the work of the IMS and the International Data Centre (IDC) were “uniquely important because of their work of prompt association on a global scale.” Association is the process in which all monitoring data on a single event from a multitude of stations are combined.

Scientists acknowledged that the verification regime’s infrastructure and analysis methods have improved greatly over the last decade. The increasing sensitivity in event detection has led to a corresponding increase in the number of progressively smaller events being registered globally by the IMS network. Several scientists said that event screening procedures needed to be further refined to face this challenge.

Around 70 percent of the infrasound stations foreseen in the Treaty have already been certified and send data to the IDC in Vienna on a continuous basis. It is expected that an additional 10 stations will be added to the network over the next three years. Alexis Le Pichon, of the Commissariat a l’énergie atomique, France, said that the infrasound network provided unique global coverage. It was larger and more sensitive than any other previously operating network.

Elisabeth Blanc of the Commissariat a l’énergie atomique, France, gave an example of the system’s ability to detect low yield explosions. On 15 March 2008 the Gerdec explosion which was caused by a fire at an ex-military ammunition depot near Tirana in Albania, was detected at four IMS infrasound stations and two stations from scientific arrays.  It had an estimated yield of around one kiloton.  Speaking about research challenges in the field, Blanc stressed that more reliable atmospheric models were needed to further improve infrasound monitoring.

A total of 55 radionuclide stations were established between June 2000 and December 2008, accounting for almost 70 percent of the total number of stations planned for the network. Scientists stated that all technical specifications have been met and the detection capability of the network meets expectation. When an underground test is conducted, the noble gas xenon is the most likely radioactive substance to escape into the atmosphere,. corroborating seismic evidence suggesting that the explosion was nuclear. Half of the envisaged number of radionuclide stations will be equipped with noble gas technology.  There has been an enormous amount of progress in the field over the last five to ten years.  More than 50 percent of the 40 stations planned for the noble gas network have now been installed.

Significant improvements over the last few years, especially in terms of regional seismic techniques, have contributed greatly to the network. Reference was made to the prompt detection and interpretation by the seismic network of signals from the nuclear explosions allegedly carried out by the Democratic People’s Republic of Korea (DPRK) in 2006 and May 2009. While 22 seismic stations registered the nuclear explosion in October 2006, less than three years later the number of stations that detected the second explosion had increased to 61. The IMS seismic network was commended in terms of the use of high-quality seismic arrays and permanent stations which, will enable new levels of capability in reporting location estimates and magnitudes.

IMS stations make important contributions to the International Seismological Centre with a very high accuracy rate. Stations making up the seismic network are capable of detecting all seismic events with a magnitude greater than 4 and magnitude 3.5 or lower in Eurasia.

The hydroacoustic network is nearing completion, with 10 of the 11 stations now certified. The network has a very high detection capability which was illustred through a marine seismic survey off the coast of Japan in September 2008. Around 20 kg of TNT were detonated, with signals picked up by IMS hydrophone sensors 16000 km away in Juan Fernandez Island in Chile.

One of the results of increased detection capabilities is the sheer volume of information – up to 9 GB daily –  transmitted to the IDC in Vienna for analysis. Scientists stressed the importance of ensuring that there is a balance between detection and screening capabilities.

Sheila Vaidya of the Lawrence Livermore National Laboratory, USA, suggested that increased application of automated data mining and data fusion procedures would “accelerate data processing and assist in improving accuracy, identifying smaller events and speeding up human review.” She further elaborated on data mining elements that already exist or are being developed and could be applied. These include the use of historical archives, machine learning, pattern recognition and fusing data from different sources.

Data mining is complementary to the other technologies by helping to reject spurious events and possibly providing more reliable detection and localization of lower magnitude events.

Conference participants agreed that the recent nuclear test by the DPRK highlighted the need for a robust and functioning on-site inspection (OSI) regime.  This ultimate verification measure can be invoked only after entry into force of the CTBT. The on-site inspection regime applies procedures, methods and techniques to find smoking-gun evidence of a nuclear explosion at the very location where it is suspected of having been conducted. The organization had come a long way in developing procedures, training inspectors and testing equipment.

For the first time, all elements of an on-site inspection were tested in synergy in the large-scale on-site inspection simulation in September 2008 in Kazakhstan - the Integrated Field Exercise 2008.  In a realistic scenario, a team of 40 inspectors used clearly defined OSI techniques to examine an area of 1000 square kilometres for clues of a recently conducted nuclear explosion.

In this first ever integrated on-site inspection simulation, the inspection team applied techniques in synergy, showing their complementary character. Also for the first time, the organization demonstrated the collection and measuring of the radioactive noble gas argon which is a by-product of a nuclear explosion.

The exercise provided a host of invaluable lessons which the CTBTO is now tasked to work through. This is helped by the over 40 scientific posters that documented the current status of scientific studies on on-site inspections.

As with the monitoring technologies, OSI inspection techniques and equipment need to keep up with technological developments. This is particularly valid for the development and improvement of mobile equipment, especially portable detectors of the radioactive noble gases xenon and argon.

Speakers acknowledged the close cooperation between the CTBTO and academic institutions in the development of OSI equipment and recommended continuing and broadening this collaboration.

Whenever scientists discuss CTBTO verification technologies and monitoring data, they inevitably get to talk about their additional uses outside the realm of verification. The ISS Conference attested again to the broad range of potential civil and scientific applications of CTBTO data and technologies.

Scientists welcomed the fact that since November 2006, the CTBTO has been contributing to tsunami warning by providing monitoring data to tsunami warning centres in the Indian and Pacific Oceans. Formal cooperation exists with a number of these centres and more have expressed an interest in receiving monitoring data.  Data from over 70 seismic and hydroacoustic stations are a potent example of how CTBTO monitoring data can be used to serve mankind.

Discussions at the Conference focused on other areas where verification data and technologies could be applied in the future.

Describing it a “renaissance of infrasound” Elizabeth Blanc referred to the influence the CTBTO’s infrasound monitoring technology has had on reviving this discipline. This was also reflected in the 30 posters on infrasound technology and its applications.
On several occasions, this technology has shown that it could be capable of contributing to disaster mitigation, human welfare and scientific research.   Alexis Le Pichon, also of the Commissariat a l’énergie atomique, France, cited the examples of the London oil depot explosion in 2005 and the Oregon high altitude meteorite explosion in 2008, which were confidently detected by several IMS infrasound stations.  Other applications include warning civil aviation about volcanic ash plumes for, hurricane monitoring and many scientific research projects on the atmosphere.

The hydroacoustic monitoring network is the smallest of the IMS networks but is recognized as having great potential in contributing to disaster mitigation and scientific research.  In addition to tsunami warnings, other contributions concern research of the oceans, their geology and biology, seismic activities under the oceans and the creation and movement of icebergs.  

Dmitry A. Storchak of the International Seismological Centre highly valued the contribution of CTBTO seismic data to the global collection of data on earthquakes. Due to its global coverage, the IMS seismic network can provide data where other networks are not present such as in oceanic and remote areas of the globe.  Barbara Romanowicz of the University of California, USA, mentioned the important contribution of seismology to tsunami warning efforts. She also said that the seismic data could help boost studies on the Earth’s structure and its magnetic field.

Atmospheric Transport Modelling (ATM) is another field where the world of science could benefit from CTBTO data input.  ATM is used to backtrack radioactive substances to their point of emission. In conjunction with infrasound monitoring, Richard Hogue of the Meteorological Service of Canada stated that such models could also be used to improve the monitoring of volcanic ash plumes to improve civil aviation safety.

One of the fundamental themes of the Conference was the role that science plays in global security. Russian academician Evgeny N. Avrorin reitereated the importance of science in the reduction of global security threats. While he explained that “scientific discoveries and developments are the basis of all weapons of mass destruction,” he also stressed “international cooperation in science and technology can promote a climate of confidence.”

Speaking on the relationship between science and security, Raymond Jeanloz of the US National Academy of Sciences emphasized that “science and technology are crucial for counter-proliferation and arms control.” He added that "broad technical capabilities would be needed even more in the future to prevent biological threats and to counter terrorism."

The general consensus was that the ISS project assessment came at a very timely moment, adding greatly to the credibility of the verification regime. The work that has been carried out by the project is of significant global value and the high turnout reflected the commitment of the international scientific community to the project. The Conference was described as unusual in terms of having more to do with communicating with other scientists and appealing to a broader audience.

Looking ahead, participants emphasized the need for continued dialogue and the importance of follow-up activities including future scientific conferences CTBT verification issues. The ISS Conference was considered a major milestone in the collaboration between the CTBTO and the scientific community. Participants repeatedly stressed the need for an increased availability of CTBTO monitoring data to scientists around the world. As Peter Chen of the World Meteorological Organization put it: “Data are best used when shared.” The sharing of monitoring data would immensely benefit the many research projects that scientists are undertaking to improve the CTBTO’s verification capacities. It would also give an impetus to further research into the civil and scientific applications highlighted during the Conference.