U.S. Department of Energy Geothermal Technologies Program Exploration Peer Review Report

1. U.S. Department of EnergyGeothermal Technologies ProgramExploration Peer Review Report ProjectTitle:Assembling Crustal Geophysical Data for Geothermal Exploration in the Great Basin CPS Identifier: 12339 Principal Investigator:John N. Louie Sponsoring Organization: University of Nevada, Reno www.seismo.unr.edu/geothermal

2. Project Purpose • Assemble 3-d reference model of seismic velocity for the western Great Basin • Understand deep heat sources • Can crustal thickness be a resource indicator? • Improve regional models of resource geology • Assist USGS national geothermal assessment

3. Moho Depth Pg Pn Regional Geothermal Assessment 1990 Geophysical Framework grids Poor Detail in No. Nevada

4. Gradient of index Index Geothermal Index from crustal properties of 1990 Diamond size from kilowatts produced

5. Lack of Post-60’s Refraction Coverage

6. Project Objectives • 3-d reference model of seismic velocity for the western Great Basin • “Contribute critical data toward the effective exploration for new geothermal resources” • Fill in poorly characterized areas • Develop a community model contributed to regional assessment activities • Evaluate geophysical indicators of geothermal resources • Build academic infrastructure and technical workforce in geothermal science and technology

7. Funding DOE funding to the University of Nevada, Reno has been delayed approximately one year for this project. FY 05 funding has not yet been received.

8. Plans and Approach • Five Tasks: • Compile existing crustal information • Establish a facility for long-range crustal surveys • Develop new regional seismic-refraction technology • Collect three new crustal refraction profiles • Integrate new and prior results; create a regional crustal model; make model available to others

9. Selected Milestones

10. Results 1. • Compile existing crustal information • Establish a facility for long-range crustal surveys • Develop new regional seismic-refraction technology • Collect three new crustal refraction profiles • Integrate new and prior results; create a regional crustal model; make model available to others

11. Complete Compilation of GB Crustal Thicknesses

12. Results 2. • Compile existing crustal information • Establish a facility for long-range crustal surveys • Develop new regional seismic-refraction technology • Collect three new crustal refraction profiles • Integrate new and prior results; create a regional crustal model; make model available to others

13. 21 “Texans” from Refraction Technology, Inc.

14. Results 3. • Compile existing crustal information • Establish a facility for long-range crustal surveys • Develop new regional seismic-refraction technology • Collect three new crustal refraction profiles • Integrate new and prior results; create a regional crustal model; make model available to others

15. 3 km wide Blast C 80,000 lbs ANFO 40-ft Benches >400 m deep Anatomy of a Nevada Gold MineDaily seismic sources of opportunity

16. 200 “Texans” from PASSCAL and DOE/GBCGE

17. The N. Walker Lane Experiment, 2002

18. Data & Synthetics Reduced by 7.4 km/s

19. May 21 M1.6 Earthquake Near Bridgeport Small 1st arrival clear at 100s of km

20. Results 4. • Compile existing crustal information • Establish a facility for long-range crustal surveys • Develop new regional seismic-refraction technology • Collect three new crustal refraction profiles • Integrate new and prior results; create a regional crustal model; make model available to others

21. The N. Walker Lane Experiment, 2002

22. ? Horizontal Rays ? Refraction “Tunneling” 7.2 km/s Moho How Thick is the Crust? Journal Publication: Louie, J. N., W. Thelen, S. B. Smith, J. B. Scott, M. Clark, and S. Pullammanappallil, 2004, The northern Walker Lane refraction experiment: Pn arrivals and the northern Sierra Nevada root: Tectonophysics, 388, 253-269.

23. August2004 Long Valley Fresno Las Vegas Idaho-Nevada-California (INC), 2004

24. UNR’s 21-Texan Facility Round Mtn. Mine Programming Recorders Downloading Data 400 “Texans” from PASSCAL and DOE/GBCGE

25. Aug. 2004 INC Recording

26. Aug. 2004 INC Recording - 500-km distances

27. 8/05 5/02 8/04 Spanning the Region

28. Results 5. • Compile existing crustal information • Establish a facility for long-range crustal surveys • Develop new regional seismic-refraction technology • Collect three new crustal refraction profiles • Integrate new and prior results; create a regional crustal model; make model available to others

29. Purple circles = Extensional White squares = Magmatic Extensional-type geothermal systems correlate with areas of thin crust while magmatic systems correlate with areas of thicker crust Colors = crustal thickness, warmer = thinner (includes new data IDW, nn, po = 5) Circles with dots = new seismic data Numbered labels = difference between new and old data in kilometers Buffer around new data = radius 100 km where old data removed for interpolation Considering New Crustal Thicknesses- M. Coolbaugh

30. Compilation of Selected Crustal Thicknesses

31. Impact of Work/Merit • New technology for national/regional assessments • Progress toward improving success rate for finding resources at undrilled sites to 40% • Thin crust helps locate Buffalo Valley prospect • Technology transfer: • Websites, Journal paper, 2 GRC papers, SEG paper, International conference, 7 other US workshops • Collaborators: IRIS/PASSCAL, Optim Inc., LLNL, GBCGE • Workforce development: • 20 student field hands, 8 student co-authors, senior thesis, 2 MS theses, PhD thesis

32. Plans for Completion • Final 2 project years have reduced funds • Publish INC results • Collect Utah transect 8/05, report results, publish • Integrate new results into Great Basin model • Gather industry feedback on regional model • Publish and deliver model to collaborators and groups doing regional assessment • Heimgartner graduates with MS degree by 9/07