November 2008Infrasound Technology Workshop, Bermuda Page 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 DivisionInternational Monitoring System DivisionPreparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty OrganizationProvisional Technical SecretariatVienna International CentreP.O. Box 1200A-1400 ViennaAustria

E-mail: John.Coyne@ctbto.org

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Outline

Introduction

Equipment

Progress

Status

Future Activities

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IntroductionRecognizing 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

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Experimental Array: Equipment Geometry

Equipment to meet IMS specifications

Each of the 4 sites consists of:MicrobarometerDigitizer with storage (> 3 months)Power supply (batteries and solar panels)Wind reduction systemMet data recorded at the central element

One set of spare equipment

Geometry of 4-element infrasound array

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Experimental Array: Equipment Housing

Figure showing the organization of the electronic equipment in the plastic box and their connection to the external devices

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Experimental Array: Wind Reduction System

Rosette filter configuration

Six porous hoses

Each hose 15 metres long

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Experimental Array: Equipment List

Quantity Equipment Station Spare Total

Microbarometer 4 1 5 Digitizer with externa GPS antenna and cable set (signal, power, GPS and configuration cables)

4 1 5

Charge controller 4 1 5 Equipment box 10 0 10 Batteries 65Ah None (purchased at the site) Solar panels 80W 8 2 10 Adjustable frames for solar panels 8 0 8 Temperature sensor 1 1 2 Wind speed sensor 1 1 2 Meteorological mast 1 0 1 Manifold (6 inlets) 4 1 5 Porous hose (each 15m long) 24 4 28 Plastic pipe or (each 1.5m long) 4 1 5 Heavy-duty rubber hose 4 1 5 Cable gland 8 2 10 Laptop 1 0 1 Alarm system 4 0 4 Lock 4 0 4 Cable for solar panel to equipment box 8 0 8 Cable for wind sensor to equipment box 4 0 4 Cable for temperature sensor to equipment box 4 0 4

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Experimental Array: Equipment in Vienna

Met StationEquipment Box

GPS

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Experimental Array: Equipment with model

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Experimental Array: Equipment Housing

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Experimental Array: Wind Reduction System

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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)

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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)

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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

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Regional Context

Chile

Argentina

PLCAI01AR

105 km

Potential Deployment Area

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Initial Deployment: Planned for Chile

ArgentinaChile

Llama

Villarrica

Nearby towns

53 km

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Volcanic eruption earlier this year in Chile

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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

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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