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The Importance of International Seismic Networks for Tsunami Warning

The Importance of International Seismic Networks for Tsunami Warning. Stuart A. Weinstein and Charles McCreery, Richard Hagemeyer Pacific Tsunami Warning Center. Int. Seismic Networks Are Instrumental To The Tsunami Warning System

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The Importance of International Seismic Networks for Tsunami Warning

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  1. The Importance of International Seismic Networks for Tsunami Warning Stuart A. Weinstein and Charles McCreery, Richard HagemeyerPacific Tsunami Warning Center

  2. Int. Seismic Networks Are Instrumental To The Tsunami Warning System • They allow the warning system to respond quickly to any potential tsunamigenic earthquake occurring anywhere in the world. • Contribute to the monitoring of “local” earthquakes.

  3. Int. Seismic Networks Are Instrumental To The Tsunami Warning System • With a Satellite dish, PTWC has a first hop capability for several instruments. • Currently PTWC, receives MIDW, RPN, JOHN and WAKE, with XMAS, KANT, and TARA to be received in the near future.

  4. Earthquake Monitoring • Near Real Time Seismic Data From Over 130 Broadband Stations. • Digital Alarms • Automatic P-Wave Picking And Association (GLASS, LOC_ATWC) • Magnitude Estimation: Mwp, Mm, Ms • Energy/Moment ratio (Newman and Okal)

  5. Broadband Seismometer Distribution Vertical Component Only

  6. Earthquake Monitoring • Mwp (Tsuboi et al.) • P-wave method (fast!) developed for deep focus earthquakes found to work for shallow quakes. • Less affected by Saturation Problem Associated with Ms. • Can be fooled by complex rupture (Peru 2001).

  7. Mwp and Local Earthquakes • Mwp is limited by the trade off between the S-P travel time, and the source duration of the event. • Appears to work well at less than 5 degrees epicentral distance. Depending on the Mw and source length, Mwp provides an estimate that is low by an amount that decreases between 1-5 degrees epicentral distance. • Will automate it for local earthquakes.

  8. 84 Mwp Observations Within 5 Degrees of The Epicenter

  9. Earthquake Monitoring • Mantle Magnitude (Okal and Talandier) • Long Period Rayleigh Waves that Sample the Upper Mantle (Mantle Waves). • Overcomes Saturation Problem Associated with Ms (Variable Period Magnitude). • Less Effected By Rupture Slowness Or Complexity. • Quicker Than Computing CMT.

  10. Sampling by Max Mm Mean Residual Sampling by Max of Mean Mm(T) Mean Residual Harvard Mw

  11. 273s 163s 51s Mean Residual Mean Residual

  12. EARTHWORM ARCHITECTURE PICK MODULE IMPORT MODULE WAVE- FORM RING LAN/WAN MAGN MODULE PICK RING EXPORT MODULE HYPS RING LAN/WAN ASSOC HYPS MODULE SINGLE PLATFORM (NT OR SOLARIS)

  13. IMPORTANT EARTHWORM FEATURES • FREE AND AVAILABLE OFF OF THE WEB • HTTP://GLDBRICK.CR.USGS.GOV • OPEN SOURCE (FREE SOURCE CODE) • LARGE AND GROWING USER COMMUNITY • USERS GROUPS FOR PROBLEMS • USERS GROUP FOR DEVELOPERS • ANSS STANDARD FOR US SEISMIC NETWORKS

  14. Food for Thought • Greater global network density. How dense? • Leverage off of the assets being devoted to DART systems: • Communications. • Successor to the STS-1 very broadband seismometer. • Ocean Bottom Seismometers • Hydrophone Arrays

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