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Spring AGU Meeting G21A-03 Fort Lauderdale, Florida May 27, 2008

The Future of USGS Earthquake Geodesy DRAFT by Hudnut, K., N. King, J. Murray-Moraleda, E. Roeloffs and Y. Zeng (presented by Greg Anderson). Spring AGU Meeting G21A-03 Fort Lauderdale, Florida May 27, 2008. Future of USGS Earthquake Geodesy. DRAFT. DRAFT. Writing team members each

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Spring AGU Meeting G21A-03 Fort Lauderdale, Florida May 27, 2008

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  1. The Future of USGS Earthquake GeodesyDRAFTbyHudnut, K., N. King, J. Murray-Moraleda, E. Roeloffs and Y. Zeng (presented by Greg Anderson) Spring AGU Meeting G21A-03 Fort Lauderdale, Florida May 27, 2008

  2. Future of USGS Earthquake Geodesy DRAFT DRAFT Writing team members each tapped by David Applegate - flat budget - slightly incr. Requested by Program Office after SESAC recommen- dation

  3. Future of USGS Earthquake Geodesy • Recommendations - highlights • Maintain current level of operations and maintenance long-term for stations along the San Andreas fault system and in urban areas • Improve staffing for observational geodetic investigations • Use geodetic data in seismic hazard maps • Use geodetic data in real-time data products, e.g., ShakeMap • Integrate processing and data products with PBO • Enhance and upgrade real-time operations to fulfill Stafford Act mandate - provide earthquake alerts

  4. Principals • Stafford Act • 42 U.S.C 5201 et seq. The Disaster Relief Act of 1974, Section 202(a) • "The President shall insure that all appropriate Federal agencies are prepared to issue warnings of disasters to State and local officials." • The Director of the Geological Survey, through the Secretary of the Interior, has been delegated the responsibility to issue disaster warnings "...for an earthquake, volcanic eruption, landslide, or other geologic catastrophe.”

  5. Principals - Partnership • USGS - NSF Interagency Memorandum of Understanding; Annex on EarthScope (italics added for emphasis) • 8.2 Plate Boundary Observatory The USGS will cooperate and collaborate fully with planning and implementation of the PBO effort. USGS support for PBO will include advice and consultation by USGS experts on the installation and maintenance of GPS receivers and borehole strainmeters, seismometers, accelerometers, magnetometers and tiltmeters, as well as consulting advice on data processing for borehole strainmeters and on imagery and geochronologic data acquisition. The USGS will also provide, through their Albuquerque Seismological Lab and other Earthquake Hazards Program offices, cooperation in the installation of GPS stations at selected ANSS stations. The Earthquake Hazards Program will continue to support existing continuous GPS stations along the San Andreas and San Jacinto faults, and in the urban area of southern California, in accord with the PBO Nucleus transition, and will continue to maintain and support selected USGS borehole strainmeters that it has installed in the western U.S. The USGS will also provide data from existing USGS GPS receivers and borehole strainmeters to designated EarthScope data repositories. For stations it operates, USGS will support PBO data products, data distribution, and archiving activities.

  6. Transition to USGS Status Slidesby Adrian Borsa (now at UNAVCO)

  7. The USGS-SCIGN GPS Network • 17 of 95 sites are telemetered in real time. • Partnering with Riverside Co. and L.A. City to immediately convert 10 more to real time. • Half the network will be real time in another year. • UNAVCO is upgrading stations • BUT… • Currently, real time sites are primarily used to broadcast corrections to surveyors. • No USGS use or processing of the real time data yet.

  8. The USGS-SCIGN GPS Network • 20 of 95 sites are telemetered in real time. • Partnering with Riverside Co. and L.A. City to immediately convert 10 more to real time. • Half the network will be real time in another year. • BUT… • Currently, real time sites are primarily used to broadcast corrections to surveyors. • No USGS use or processing of the real time data. • SO… • RTG (Real Time GIPSY) is being evaluated as a possible solution. RTG uses JPL’s GDGPS to correct clock and orbit errors, which eliminates the need for base stations in processing. Big advantage for real-time applications over large areas. • Currently, we are receiving data from two sites: GOLD and SHOP.

  9. SHOP Day 230 east Day 231 Day 232 Day 233 Day 234 Day 235

  10. SHOP east StdDev = 3.0 cm north StdDev = 6.4 cm up StdDev = 9.5 cm

  11. GOLD Anomaly east

  12. Summary of RTG Processing Results • Noise levels are considerably higher (3x) than for medium-baseline double difference processing. • Noise is highly autocorrelated, similar to that seen in double-difference processing. • Noise patterns repeat at sidereal periods due either to multipath or unmodelled satellite clock/ephemeris correction(s). • Large anomalies often repeat at sidereal periods. • Anomalies associated with rising satellites are qualitatively similar to a coseismic signature and could appear simultaneously at sites that are near each other. • Coseismic offsets of 0.50 m or more can be detected unambiguously using RTG, making it potentially useful for earthquake early warning for sites on the SAF. • Rapid determination of static displacements would be tricky using sites that are not directly on a fault. Offsets under 0.25 m could be difficult to confirm without 2~4 hours of data or more. • The potential for false alarms in the service of earthquake early warning is very real.

  13. Summary • O & M funds are “bare bones” and do not include upgrades (e.g., telemetry for real-time or replacement of old receivers, radios, etc.) • Real-time telemetry is being more broadly supported now • Cost savings, e.g. existing USGS-operated ‘former SCIGN’ and the PBO Salton net - radios compared with CDMA with recurring costs (Walls) • Scientists supported real-time at latest UNAVCO meeting (show of hands strongly in favor of going in the direction of real-time, if it can be afforded) • For prototype Earthquake Early Warning (EEW) system development (USGS) • USGS now has a long-term plan called the Geodesy White Paper that is nearly done, and will be released as an Open-File Report and available for comments prior to next budget cycle • USGS will continue to collaborate long-term with UNAVCO through the NSF-USGS Interagency MOU annex on EarthScope

  14. Questions? Ken Hudnut * U. S. Geological Survey 525 S. Wilson Ave. Pasadena, CA 91106 (626)583-7232 hudnut@usgs.gov * or co-authors of white paper: N. King, J. Murray-Moraleda, E. Roeloffs and Y. Zeng

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