Australian Infrasound Resources and Projects

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Australian Infrasound ResourcesandProjects

• David Brown
• Geoscience Australia
• ph 61-2-6249-9024
• Email David.Brown_at_ga.gov.au

July 2003
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Outline
Australian Resources Geoscience
Australia Australian National University Austral
ian Projects Nuclear Monitoring Volcano
Monitoring Bird Migration GAs Projected
Capability (12-18 months) Possible NSF Funded
Infrasound Projects
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• Resources
• Geoscience Australia
• Operating 4 of the 5 Australian IMS infrasound
  stations
• I06AU Cocos. Is, operational
  Sept. 2005
• I05AU Bucklands, Tas currently
  operational, sending data to Vienna
• I04AU Shannon, WA, operational Mar.
  2005
• I03AU Davis, Antarctica, operational Dec.
  2006
• Likely to provide assistance/advice on the
  Rabaul installation

Rabaul
Tennant Creek
July 2003
Shannon
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Cocos Is.
Bucklands
Davis
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• Resources
• Geoscience Australia
• Responsible for processing data from all 5
  Australian IMS infrasound stations
• Recently (3 months ago) initiated processing of
  IMS infrasound data (I07AU)
• Automatic signal detection (INFER)
• Analyst review
• High-speed numerical modeling of fluid flow and
  wave propagation problems
• Beowulf cluster (coming)

July 2003
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• Resources
• Australian National University
• Operating 1 of 5 Australian IMS infrasound
  stations
• I07AU Tennant Creek, NT currently
  operational, sending data to Vienna
• 2 years of archived data
• 27 years of (largely inaccessible) archived data
  from earlier WRAI array

July 2003
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1980 Chinese Nuclear Detonation, Lop Nor, 4 Mt
Gravity
Acoustic
Acoustic
Acoustic
75 microbar
0
60
30
120
90
after Christie
minutes
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• Resources
• Australian National University
• World class supercomputer facility
• Developed INFER automatic infrasonic detection
  algorithm

July 2003
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INFER Motivation

• Acoustic signal from shuttle launch STS-96
  recorded at DLIAR, Los Alamos
• a significant signal
• Distinct lack of
• correlation
• amplitude
• Signal presence is obvious to the human eye due
  to the dominant azimuth and trace velocity

STS-96
DLIAR, Los Alamos
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INFER the Hough Transform
Pairs of points (xi,yi) get mapped to the point
(m,t) where
Image Space, S
Parameter Space, P
Hough Transform
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INFER the Hough Transform
Parameter Space, P
Image Space, S
STS-96
Hough Transform
DLIAR, Los Alamos
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INFER 3D array geometry
3.5
3
2.5
Sz (s/km)
2
1.5
1
radius acoustic slowness
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2
3
2
1
1
0
0
-1
-1
Sy (s/km)
-2
-2
Sx (s/km)
-3
-3
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INFER detection results
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INFER detection results
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• INFER
• makes a single detection per phase
• Fortran code complete (minor bugs)
• C-code ready for testing
• dynamically populates various CSS database
  tables
• arrival
• detection
• infra_features
• lastid
• wfdisc
• psd_frequency
• infra_psd
• infra_noise_models
• determines PSD for every 1/2 hour for every
  channel

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INFER PSD measurement
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INFER PSD noise models
I10CA high noise model
I10CA low noise model
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INFER PSD measurement
I33MG high noise model
I33MG low noise model
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• Projects
• Nuclear Monitoring
• Satisfying Australian Governments obligations
  to monitor compliance of the CTBT
• near-real time processing of data from 5 IMS
  infrasound stations
• Automatic signal detection
• INFER detection algorithm currently operational
  at Geoscience Australia
• Automatic source location
• operational by the end of 2003
• Analyst review
• recently initiated, ongoing development of
  analyst procedures
• Source characterisation and discrimination
  analyses
• localised large-scale open-cut mining activity
• Tripartite sub-net I04AU, I05AU, I07AU
  uniquely positioned to do source location analyses

July 2003
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• Projects
• Volcano Monitoring
• Prompted by a call by the Airlines to develop a
  multi-technology early warning system for
  volcanic ash.
• Consortium of Australian companies and
  government organisations formed to determine if
  it is possible to create a multi-technology
  volcanic ash monitoring system for aircraft
• Vulcan-AUS group
• Bureau of Meteorology
• Qantas
• Geoscience Australia
• CSIRO
• Airservices Australia
• Formed in mid-1980s in response to a volcanic
  ash encounter of a British Airways 747 over
  Indonesia.

July 2003
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• Projects
• Volcano Monitoring
• GAs role
• Perform usual near-real time automatic signal
  detection of IMS infrasound array data
• Siphon off detections from a near-real time
  event list that are within a few degrees of known
  volcanic activity
• email event list to interested persons
• microbarom false alarms may be significant
• seasonal erosion of propagation ducts will also
  occur

July 2003
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• Projects
• Bird Migration
• does infrasound have a role to play in the
  migration of birds to wetland areas during major
  flooding events ?
• GAs role
• systematically process data during periods of
  known flooding and search for anomalous
  infrasonic signals

July 2003
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• GAs Projected Capability 12 to 18 months
• Real-time processing of data from several
  infrasound arrays
• Tennant Creek, Northern Territory
• Hobart, Tasmania
• Shannon, Western Australia
• Generation of an automatic detection list
• various CSS database tables dynamically
  populated
• Rudimentary source location of GT events
• use crossing azimuths, time used to preserve
  causality
• use observed departures from great-circle to
  refine source location procedure

July 2003
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Possible NSF funded infrasound projects

• Volcano Early Infrasound Warning System (VEIWS)
• need to perform research that will determine if
  a significant early warning for volcanic ash can
  be reliably given via a precursory infrasound
  signal
• do magma chamber rumbles generate atmospheric
  acoustic signals prior to venting ?
• What instrumentation is required to measure the
  signal ?
• What are the signal chracteristics ?
• Will require near-real time infrasound data
  processing
• May require development of a sophisticated
  real-time numerical microbarom filter
• A starting point may be Olsons Analytical
  signal technique

July 2003
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Possible NSF funded infrasound projects

• Grand-Challenge numerical infrasound algorithm
• Will
• solve the basic Navier-Stokes equations on an
  ellipsoid
• be fully non-linear
• be non-hydrostatic
• include acoustic-gravity modes
• use as input NRL climatological and
  environmental data
• accurately model physics from a
  highly-nonlinear source region to the completely
  linear far-field
• Suitable for operation on the
• Earth Simulator supercomputer
• A Beowulf cluster
• Will include
• topography
• acoustic radiation from the ocean surface
• solar tides

July 2003
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Possible NSF funded infrasound projects

• Grand-Challenge numerical infrasound algorithm
• Purpose
• Infrasound can catch up with all other
  geophysical modelling efforts.
• assess the validity of other modelling
  procedures
• ray tracing
• modal calculations
• parabolic approximation
• Better understand
• Microbarom radiation and to what extent it heats
  the atmosphere
• The phenomenon of Mountain Associated waves
• Acoustic scattering and diffraction
• Accurate source location

July 2003
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