Listening without sound - CTBTO engineers
refine a unique technique Page 1

New Facility to Improve Detection of Nuclear Explosions.

Although this is the second day of June, near the summit of the 1100-metre high Trafelberg, gusts of wind blow umbrellas inside out and a sharp rain is scudding into the faces of the few hardy people who've ventured outside.

Among them is Alfred Kramer, an Austrian electronics engineer, who is explaining the function of dozens of molehill like mounds of gravel, linked by spokes of tubes to raised hubs, within a security fenced enclosure.

There are, at a variety of mostly isolated locations on earth, more than 40 sites using similar equipment, as puzzling to the uninitiated as Prince Henry the Navigator’s compass rose, with which the infrasound arrays at first glance look alike, must have appeared in the fifteenth century.

This complex is in Austria, not 90 minutes from the heart of its capital Vienna, in a range of limestone hills that extend south of the city, near the bucolic village of Muggendorf.

And as Kramer is explaining, to a news crew from the Austrian national broadcaster ORF, the strange pipe arrays are test beds for a relatively obscure technology that is part of a global system to detect nuclear explosions.

Inaudible Sounds

Kramer is a technician with the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) and the Trafelberg facility is a proving ground for infrasound, which is able to detect sounds below the ability of the human ear to hear.

Infrasound test facilities at the Conrad Observatory.

For ten years Kramer has been part of a small team of CTBTO infrasound technicians wiring the planet with a global alarm system against nuclear explosions.

Presently more than 250 stations transmit, mostly by satellite, data from seismic, hydroacoustic, radionuclide and infrasound monitoring stations to the CTBTO’s International Data Centre in Vienna. When the CTBTO International Monitoring System (IMS) is completed it will keep watch from 337 facilities.

On this unseasonably cold and blustery day -- snow is falling at an elevation just a few hundred metres higher -- the CTBTO facility, at the Conrad Observatory, one of Europe’s most modern earth science research stations, is having its official opening.

Least Magnetic Location

The observatory, seven km. from the nearest public road, is operated by the Austrian Central Institute for Meteorology and Geodynamics (ZAMG). Its location was selected because this is the least magnetic site in Austria.

Viktor Conrad, for whom the observatory is named, was a famous Austrian seismologist whose socialism put him at odds with Austria’s Nazi rulers and led to his exile in the United States in 1938. Upon his death in 1962, his widow bequeathed most of the couple’s assets to the establishment of the observatory.

The infrasound test facility provides the CTBTO with the tools to refine a technology whose development at the time the Treaty was signed in 1996 had been neglected for over 30 years.

“Infrasound has a potential that is not fully understood or fulfilled,” diplomats and journalists attending the opening are told by Federico Guendel, Director of the International Monitoring System.