1. Gravity Janice Kukuk Rob Ghigieri Ross Whitmore http://sciencefun.wordpress.com/2008/04/

2. Takehome Message Bolstered NE portion of the Truckee Meadows Basin (TMB) Gravity dataset Hidden Valley Sub-basin

3. Purpose Learn how to use a Gravimeter Fill data gaps in TMB dataset Profile a smaller sub-basin in Hidden Valley

4. Location

5. Methods LaCost and Rhomberg Gravimeter Grav2d GM-SYS Trimble GPS Theodolite

6. Results for Prater ~14 mGal anomaly WEWE Distance in km Grav2d GM-SYS

7. Results for Hidden Valley Tolerance 2 mGal Density contrast-0.33 g/cc -6 mGal Anomaly WEWE Grav2d GM-SYS Distance in km

8. Comparison of results Prater (Modified from Widmer et al., 2007) WEWE

9. Comparison of results Hidden Valley WEWE

10. Error Non-equilibrated spring Terrain corrections Elevation error Inconsistent temperature User error Instrument drift

11. Future Work Verification of Hidden Valley anomaly Completion of D’Andrea pkwy line to bolster dataset

12. Takehome Message Bolstered NE portion of the Truckee Meadows Basin (TMB) Gravity dataset Hidden Valley Sub-basin

13. References Abbot, R.E., and Louie, J.N., 2000, Depth to bedrock using gravimetry in the Reno and Carson City, Nevada, Area basins: Geophysics, V. 65, p. 430-450. Anderson, J., Su, F., Zeng, Y., 1999, Seismic Hazards in the vicinity of Las Vegas and Reno: Final Technical Report GS# 1434-HQ-97- GR-03044 (paper copy, 15 p.) Telford, W.M., Geldhart, L.P., and Sheriff, R.E., 1990, Applied Geophysics: New York, Cambridge University Press, 770 p. Widmer, M.C., Cashman, P.H., Benedict, F.C., Trexler, J.H., 2007, Neogene through Quaternary stratigraphy and structure in a portion of the Truckee Meadows Basin; a record of recent tectonic history: Geological Society of America Abstracts with programs, v. 39, no. 4 p.9