1. November 2007Infrasound Technology Workshop, Tokyo, JapanPage 1 Presented to: Infrasound Technology Workshop Tokyo, Japan PTS Experimental Infrasound Array John Coyne 1, Nicolas Brachet 1, Paola Campus 2, Pavel Martysevich 2 1 Software Applications Section International Data Centre Division 2 IMS Installation and Certification Group International Monitoring System Division Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization Provisional Technical Secretariat Vienna International Centre P.O. Box 1200 A-1400 Vienna Austria E-mail: John.Coyne@ctbto.org

2. Infrasound Technology Workshop, Tokyo, Japan November 2007 Page 2 Outline Why? What? How? Where? When? Summary

3. Infrasound Technology Workshop, Tokyo, Japan November 2007 Page 3 Why? Processing technique used at the IDC has demonstrated the exceptional capability of the IMS network for detecting a wide variety of signals Signals include: microbaroms, ocean surf, mountain associated waves, thunderstorms, meteorites, avalanches, aurora, rockets, aircraft, mine blasts, accidental explosions, industrial noise … Unlike earthquakes in the case of seismic data, few infrasound signals are energetic enough to be detected on a global scale by the IMS network Detection technique used at the IDC is well adapted for detecting infrasound signals, including cases of very weak signals The counterpart of such capability is the large number of genuine signals from a wide variety of sources It is important to understand and categorize these infrasound signals

4. Infrasound Technology Workshop, Tokyo, Japan November 2007 Page 4 Understanding and Categorizing Infrasound Signals Infrasound Reference Event Database (IRED): Objective Collect, review and document infrasound events of special interest Archive the data for each event into database tables Use IRED for training, testing and validation purposes Inventory IRED contains 311 events grouped in 10 categories (Nov 2007) –Explosions (18) –Volcano eruptions (35) –Earthquakes, avalanches (53) –Meteorites and Bolides (15) –Rockets (42) –Mine and quarry blasts (125) –Aircraft (13) –Cultural noise (3) –Synthetic (1) –Military (2)

5. Infrasound Technology Workshop, Tokyo, Japan November 2007 Page 5 Understanding and Categorizing Infrasound Signals The database contents are limited due to difficulties in collecting metadata about the sources, as well as limited number of observations One common procedure is to identify events originating from a given azimuth, and use available information (e.g., news, Google Earth, etc.) to look for the potential source(s) This can lead to one or more hypotheses, which requires confirmation and further investigation In order to test such hypotheses, the PTS is procuring a portable IMS-type infrasound array that can be temporarily deployed in a region of interest

6. Infrasound Technology Workshop, Tokyo, Japan November 2007 Page 6 Experimental Array Minimum Specifications (from CTBT/PC/II/1/Add.2/Appendix X) What?

7. Infrasound Technology Workshop, Tokyo, Japan November 2007 Page 7 Experimental Array: Equipment Geometry Each of the 4 sites consists of: Microbarometer Digitizer with storage (3 months) Power supply (batteries and solar panels) Wind reduction system Met data recorded at the central element One set of spare equipment Geometry of 4-element infrasound array

8. Infrasound Technology Workshop, Tokyo, Japan November 2007 Page 8 Experimental Array: Equipment Housing Figure showing the organization of the electronic equipment in the plastic box and their connection to the external devices

9. Infrasound Technology Workshop, Tokyo, Japan November 2007 Page 9 Experimental Array: Wind Reduction System Rosette filter configuration Six porous hoses Each hose 15 metres long

10. Infrasound Technology Workshop, Tokyo, Japan November 2007 Page 10 Experimental Array: Equipment List

11. Infrasound Technology Workshop, Tokyo, Japan November 2007 Page 11 Conceptual Method of Work Observation or idea Discussion between PTS and prospective participants Plan the project (dates, duration, locations, logistics, etc) Decision made concerning the proposal Exchange of letters (necessary paperwork) Provide equipment (and or analysis) training to participants Ship equipment to Country X Transport of equipment and participants to field location How?

12. Infrasound Technology Workshop, Tokyo, Japan November 2007 Page 12 Conceptual Method of Work Field observations (one or multiple sites) Analyze data Transport equipment to PTS Document findings in a report Present and discuss results at Infrasound Workshop Feed Infrasound Reference Event Database NOTE: This list is preliminary, and discussion is welcome!

13. Infrasound Technology Workshop, Tokyo, Japan November 2007 Page 13 Candidate Scenarios Participate in controlled experiments (e.g., planned explosions or field campaigns) Test different field techniques and their effect on data processing (e.g., different noise reducing systems) Investigate infrasound sources recorded by IMS stations Where?

14. Infrasound Technology Workshop, Tokyo, Japan November 2007 Page 14 Source Investigation for an IMS station Install IMS station Observe reoccurring signals at IMS station Hypothesize potential sources of infrasound signals Propose experimental array deployment to distinguish between multiple potential sources or to verify a potential source IMS station Potential Source Observed Azimuth Experimental Array

15. Infrasound Technology Workshop, Tokyo, Japan November 2007 Page 15 When? The hardware is currently in the procurement process Contract signature is expected before the end of 2007 Equipment should be available in 2Q 2008 First observations in 3Q 2008 Report first results at the next Infrasound Workshop

16. Infrasound Technology Workshop, Tokyo, Japan November 2007 Page 16 Expected Benefits The experimental array will provide a way to investigate and confirm infrasound sources Provide additional meta-data for the Reference Event Database The experimental array can also be used in controlled experiments for improving techniques When participants will gain experience with the equipment, data analysis and interpretation, and project management The results will increase our understanding of infrasound sources

17. Infrasound Technology Workshop, Tokyo, Japan November 2007 Page 17 Summary A sound understanding of infrasound sources is essential for interpreting infrasound signals Many genuine signals of unknown origin are routinely observed at IMS infrasound station The experimental array is expected to assist in understanding and categorizing infrasound signals Equipment is being procured, and first experiment should take place in mid-2008 Initial results should be presented at the next Infrasound Workshop Interested parties should contact us concerning future collaboration