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Assembling Geophysical Data to Model Seismic Response in Las Vegas Valley

Assembling Geophysical Data to Model Seismic Response in Las Vegas Valley. John G. Anderson & John N. Louie Seismological Lab, UNR May 2003 - May 2005. LVVSR Components @UNR. Model Assembler Enables LLNL to use existing knowledge Adding new data; interoperation and archiving

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Assembling Geophysical Data to Model Seismic Response in Las Vegas Valley

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  1. Assembling Geophysical Data to Model Seismic Response in Las Vegas Valley John G. Anderson & John N. Louie Seismological Lab, UNR May 2003 - May 2005

  2. LVVSR Components @UNR • Model Assembler • Enables LLNL to use existing knowledge • Adding new data; interoperation and archiving • E3D sensitivity studies • Place facilities and expertise at UNR • Guide model assembly • Shallow shear-velocity transects • Extensive reconnaissance data • Outreach • Scientific presentations; students’ careers • Link with UNLV faculty • Community and national efforts

  3. ModelAssembler • A code to stitch together existing regional geophysical and geological data sets, into a form useful to E3D.

  4. Comparison of Regional Basin Estimators Rogers’s March ‘02 5% topographic gradient result is above. Bedrock is blue and basins are yellow. (Only showing surface velocity.) Louie’s July ‘02 ModelAssembler 2.0 result is below. Bedrock is red and basins are green-to-blue. (Showing 20-km vertical velocity average.) The bedrock nature of flat Pahute Mesa is now shown, but some Tertiary sediments like the Funeral Fm. in Death Valley also show as bedrock. LV PM SM DV PM LV SM DV

  5. Regional Basin DepthsJachens and Blakely, USGSSedimentary and VolcanicDerived from Basin Gravity

  6. ModelAssembler • Uses Rules to project properties.

  7. ModelAssembler • Has existing, and some new, geotechnical measurements by UNLV and UNR.

  8. Le Rêve, LV Strip SASW courtesy B. Luke, UNLV Engineering Geophysical Lab.

  9. Soil profile Las Vegas Springs SASW & X-Hole courtesy B. Luke, UNLV Engineering Geophysical Lab.

  10. ModelAssembler • Leading to projects testing many evaluation methods at critical sites. Comparison of Dispersion Curves

  11. Tentative Software Requirements (Features of MA): Conversion and parallelization of MA completed before Ms. Yan Ha visits LLNL. 1st sequential version, debugging and optimization complete by end of October. Includeregional geophysical grids and topography in MA. Complete by end of December 2003. Develop MA3 into a Public Web Service. Under discussion with L. Kamb of SCEC/IRIS-DMC. Assuming Yan Ha visit will be from February to April 2004: Integrate MA and E3D. Complete initial test runs: 4/28/2004. ModelAssembler • Plans for integration with E3D, use by other LLNL projects, and visualization development:

  12. Add stochastic geologic/geophysical variability to assembled models. Complete stochastic method incorporation at end of April 2004. Complete stochastic-unit rule sets by end of May 2004. Complete stochastic test runs: 8/15/2004. Enable blending of embedded grids, morphing, and rule-based transitions between input dataset areas. Demonstration: 3/1/2004. Complete improved, reviewed, tested transitions: 6/15/2004. Add model visualization capability to MA. Three-dimensional visualizations available by 9/15/2004. Remove rules from code and allow them to be written plainly. Completion: 5/31/2004 (after Ms. Ha visit). Archive MA and all contributing data. Completion: 9/15/2004. ModelAssembler • More Plans:

  13. ModelAssembler • Amplification map output- a test of MA, or an outreach product?

  14. 4 dual-Athlon nodes funded by LLNL 11 additional dual-Athlon nodes funded by: Optim LLC Nevada Applied Research Initiative Research and education mission 4 lab exercises for grad/senior geophysics course now on line Collaboratory forComputational Geosciences

  15. E3D Sensitivity Tests • 2-d elastic graben model computed at CCoG

  16. E3D Sensitivity Tests • Spectral-ratio images

  17. 8 sec Period 4 sec Period

  18. 8 sec Period 4 sec Period

  19. 8 sec Period 4 sec Period

  20. E3D Sensitivity Tests

  21. Shallow Shear-Velocity Transects • Using urban ReMi reconnaissance

  22. Shallow Shear-Velocity Transects • ReMi measures Rayleigh dispersion with linear refraction arrays.

  23. Reno Transect • Local reconnaissance was first test.

  24. Reno Transect • Unexpected results:

  25. Reno Transect • Lack of V30 correlation to maps

  26. Shallow Shear-Velocity Transects • Las Vegas route from Cheyenne to Tropicana

  27. Las Vegas Transect • Some correlation to basin depth?

  28. Las Vegas Transect • No correlation between V30 and geologic map.

  29. Las Vegas Transect • Correlation with clay soils, caliche in Las Vegas?

  30. Las Vegas Transect • Shallow section & V100 hint at stratigraphy, faulting?

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