Presented to: Infrasound Technology Workshop Bermuda

1. Presented to:Infrasound Technology WorkshopBermuda PTS Portable Infrasound Array John Coyne, Nicolas Brachet, David Brown, Pierrick Mialle, Patrick Grenard, Paola Campus, Pavel Martysevich, Stefka Stefanova, Alfred Kramer, Ekrem Demirovic International Data Centre Division 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 Infrasound Technology Workshop, Bermuda

2. Outline • Introduction • Equipment • Progress • Status • Future Activities Infrasound Technology Workshop, Bermuda

3. Introduction • Recognizing the direct relationship between optimizing measurement systems and data analysis techniques, the PTS is implementing a cross-divisional project for developing and deploying a portable infrasound array • High Level Objective: to improve the contribution of infrasound detections at IMS stations into the Reviewed Event Bulletin (REB) • For example: Deployment to improve the understanding of local and regional sources of infrasound • Participate in field exercises with controlled sources to collect ground truth data and improve modeling of acoustic propagation • Evaluate the impact of station configurations on data processing • Evaluate the positioning of an IMS station which is influenced by known infrasound sources Infrasound Technology Workshop, Bermuda

4. Experimental Array: Equipment Geometry • Equipment to meet IMS specifications • 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 Infrasound Technology Workshop, Bermuda

5. Experimental Array: Equipment Housing • Figure showing the organization of the electronic equipment in the plastic box and their connection to the external devices Infrasound Technology Workshop, Bermuda

6. Experimental Array: Wind Reduction System • Rosette filter configuration • Six porous hoses • Each hose 15 metres long Infrasound Technology Workshop, Bermuda

7. Experimental Array: Equipment List Infrasound Technology Workshop, Bermuda

8. Experimental Array: Equipment in Vienna Equipment Box Met Station GPS Infrasound Technology Workshop, Bermuda

9. Experimental Array: Equipment with model Infrasound Technology Workshop, Bermuda

10. Experimental Array: Equipment Housing Infrasound Technology Workshop, Bermuda

11. Experimental Array: Wind Reduction System Infrasound Technology Workshop, Bermuda

12. Testing in Vienna, October 2008 • Alarm system test • Signal polarity test • Digitizer self-noise test • GPS time synchronization test (disable the antenna) • Power supply test • System noise test (microbarometer plugged) • Array element reset test (power off/on) Infrasound Technology Workshop, Bermuda

13. Initial Deployment anticipated in Chile • Purpose • Improve understanding of local and regional sources • Evaluate positioning of the array near active volcanoes • Context • Several potentially active volcanoes in the region • Exchange of letters ongoing • Site selection ongoing (following slides) Infrasound Technology Workshop, Bermuda

14. Initial Deployment anticipated in Chile • Potential deployment area identified based on relative location of potential sources (towns and volcanoes) • Different sources should be at different azimuths from the array • I40PG is planned to be 25 km from an active volcano Infrasound Technology Workshop, Bermuda

15. Regional Context Potential Deployment Area Argentina Chile I01AR PLCA 105 km Infrasound Technology Workshop, Bermuda

16. Initial Deployment: Planned for Chile Llama Nearby towns Villarrica Argentina Chile 53 km Infrasound Technology Workshop, Bermuda

17. Volcanic eruption earlier this year in Chile Infrasound Technology Workshop, Bermuda

18. Field deployments • Deployments are not just a matter of taking a trip with some equipment and beginning measurements • Many factors are needed for a successful campaign: • Sufficient planning • Proper site selection • Logistic issues • Equipment import issues • Security • Success also depends on dedication, effort and support from all parties involved Infrasound Technology Workshop, Bermuda

19. 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. Also assess impact of station configurations on data processing • Equipment has been procured, and first experiment should take place in early 2009 • First results should be presented at the next Infrasound Workshop • Interested parties should contact us concerning future collaboration Infrasound Technology Workshop, Bermuda