Infrasound Technology Workshop 2014

Around 90 technical experts in the field of infrasound technology from a range of research institutes and academic institutions met from 13 to 16 October in Vienna, Austria, to attend the Infrasound Technology Workshop 2014. Scientists, engineers and academics from 35 countries discussed advances in the detection of ultra-low frequency sound waves caused by nuclear explosions.

The workshop, organized by the Comprehensive Nuclear-Test Ban Treaty Organization (CTBTO), aimed at stimulating research and data sharing within the ‘infrasound family’ as well as encouraging each Member States to play an active role in the advancement of Comprehensive Nuclear-Test-Ban Treaty (CTBT) verification in this field.
It’s important that each country be confident with the collection techniques and analysis methodology employed at the International Data Centre and be able to replicate these analyses on their own – should they chose to. The Treaty cannot be effective unless we employ methods that are viewed as credible and current by the scientific community, this is why we need events like the Infrasound Technology Workshop to create and share new ideas.

Participants heard and discussed 50 presentations covering a range of topics from instrumentation to station performance to non-verification uses of infrasound data. Special emphasis was placed on the sustainability of the network of monitoring stations and improving performance by enhancing the quality of data produced by each station. In this context, CTBTO scientists explained ongoing projects aimed at redesigning and upgrading infrasound stations in order to adapt them to their surrounding natural environment.

Infrasound station IS37 station in Bardufoss, Norway has been adapted to the specific atmospheric conditions of the Norwegian forest.

Infrasound stations face challenges such as rain and snow, falling trees, as well as seasonal changes in wind patterns which affect the stations’ “field of regard”. CTBTO Acoustic Officer Pierrick Mialle explained that such challenges are the reason why “infrasound research is expected to increasingly interact with the meteorological scientific community. Such a mutually beneficial relationship is of crucial importance for finding meaning out of the data and this is ultimately necessary for the Treaty’s verification regime.”

Array element pipes of infrasound station IS36 in New Zealand have been bent around the trees.

Thanks to its global coverage, the CTBT’s network forms the backbone of international infrasound research.

Although it has been designed mainly for monitoring above ground nuclear explosions, the infrasound network helped detect an underground test after the Democratic People’s Republic of Korea (DPRK) announced that it had carried out its most recent test in February 2013. Two infrasound stations - IS45 Ussuryisk, Russia, and IS30 Isumi, Japan - picked up a signal related to the event, caused by the vibrations of the mountains under which the test took place. This helped corroborate the findings made by 94 CTBTO seismic stations.
It has been an amazing experience and I had the chance to learn more; I believe it is of crucial importance for us to meet other infrasound experts in order to advance with our researches. My country, Cameroon, is often affected by lake craters explosions. During this workshop, I could compare findings on the topic with colleagues.

Several talks at the workshop were dedicated to the spin-offs of infrasound monitoring for purposes other than CTBT verification. Events that can be studied using IMS infrasound data include volcanic eruptions, earthquakes, tsunamis, meteor blasts, thunderstorms and avalanches. While the detection of these phenomena is not part of the CTBTO’s verification mandate, such knowledge benefits the organization because natural events can be screened out more effectively.

Infrasound waves are acoustic waves with very low frequencies, inaudible to the human ear.

For my country, studying infrasound technology is of crucial importance. In particular, Africa is affected by volcanic eruptions and seismic activities. We need to keep on using the infrasound technology and make attempts in order to associate findings and characterize volcanic and seismic aspects.

The subject of infrasound monitoring has played an important role since the earliest negotiations on verifying a nuclear test-ban treaty.  Infrasound technology was used in the 1950s and 1960s by the United States and the Soviet Union to monitor each other’s atmospheric nuclear tests. After the Partial Test Ban Treaty entered into force in 1963, testing was driven underground. The technology was thus not developed further until the CTBT’s negotiations in the mid-1990s, when it experienced a renaissance. Today, the CTBTO is the world’s only organization to operate an infrasound network of stations with global coverage.

The IMS infrasound network: click for interactive map

Every year an increased number of people attend the Infrasound Technology Workshop, this also means that more people are aware of the topic of infrasound, its concrete applications and the CTBTO’s mission […] besides technical coordination, we have the duty to educate people and explain what the infrasound technology can give to us.