1 / 25

Australian Infrasound Resources and Projects

Australian Infrasound Resources and Projects. David Brown Geoscience Australia ph: +61-2-6249-9024 Email: David.Brown@ga.gov.au. July 2003. 1. Outline. Australian Resources Geoscience Australia Australian National University Australian Projects Nuclear Monitoring Volcano Monitoring

nasim-gonzales
Download Presentation

Australian Infrasound Resources and Projects

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Australian Infrasound ResourcesandProjects David Brown Geoscience Australia ph: +61-2-6249-9024 Email: David.Brown@ga.gov.au July 2003 1

  2. Outline • Australian Resources • Geoscience Australia • Australian National University • Australian Projects • Nuclear Monitoring • Volcano Monitoring • Bird Migration • GA’s Projected Capability (12-18 months) • Possible NSF Funded Infrasound Projects 2

  3. 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 theRabaulinstallation Rabaul Tennant Creek July 2003 Shannon 3 Cocos Is. Davis Bucklands

  4. 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 4

  5. 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 5

  6. 1980 Chinese Nuclear Detonation, Lop Nor, 4 Mt Gravity Acoustic Acoustic Acoustic 75 microbar 0 60 30 120 90 [after Christie] minutes

  7. Resources • Australian National University • World class supercomputer facility • Developed INFER automatic infrasonic detection algorithm July 2003 7

  8. 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 INFER: Motivation STS-96 [DLIAR, Los Alamos]

  9. 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

  10. INFER: the Hough Transform Parameter Space, P Image Space, S STS-96 Hough Transform [DLIAR, Los Alamos]

  11. INFER: 3D array geometry 3.5 3 2.5 Sz (s/km) 2 1.5 1 radius = acoustic slowness 3 2 3 2 1 1 0 0 -1 -1 Sy (s/km) -2 -2 Sx (s/km) -3 -3

  12. INFER: detection results

  13. INFER: detection results

  14. 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

  15. INFER: PSD measurement

  16. INFER: PSD noise models I10CA high noise model I10CA low noise model

  17. INFER: PSD measurement I33MG high noise model I33MG low noise model

  18. Projects • Nuclear Monitoring • Satisfying Australian Government’s obligations to monitor compliance of the CTBT • near-real time processing of data from 5 IMS infrasound stations • Automatic signal detection • INFER detection algorithmcurrently 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 18

  19. 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-1980’s in response to a volcanic ash encounter of a British Airways 747 over Indonesia. July 2003 19

  20. Projects • Volcano Monitoring • GA’s 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 20

  21. Projects • Bird Migration • does infrasound have a role to play in the migration of birds to wetland areas during major flooding events ? • GA’s role: • systematically process data during periods of known flooding and search for anomalous infrasonic signals July 2003 21

  22. GA’s 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 22

  23. 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 Olson’s Analytical signal technique July 2003 23

  24. 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 24

  25. 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 25

More Related