Enhancing Gravity Data in the Truckee Meadows Basin: Gravimetric Analysis of Hidden Valley
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This study focuses on bolstering the gravity dataset for the Truckee Meadows Basin (TMB) by conducting a gravimetric survey in the Hidden Valley sub-basin. Utilizing LaCost and Rhomberg Gravimeters, Grav2D, GM-SYS, Trimble GPS, and theodolite, we aimed to fill in data gaps and profile this smaller sub-basin. Our results reveal a 14 mGal anomaly in the Prater area and a -6 mGal anomaly in Hidden Valley, highlighting the density contrast and potential geophysical insights. Future work will involve verifying anomalies and completing the D'Andrea Parkway line.
Enhancing Gravity Data in the Truckee Meadows Basin: Gravimetric Analysis of Hidden Valley
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Presentation Transcript
Gravity Janice Kukuk Rob Ghigieri Ross Whitmore http://sciencefun.wordpress.com/2008/04/
Takehome Message • Bolstered NE portion of the Truckee Meadows Basin (TMB) Gravity dataset • Hidden Valley Sub-basin
Purpose • Learn how to use a Gravimeter • Fill data gaps in TMB dataset • Profile a smaller sub-basin in Hidden Valley
Methods • LaCost and Rhomberg Gravimeter • Grav2d • GM-SYS • Trimble GPS • Theodolite
Results for Prater Grav2d W E GM-SYS ~14 mGal anomaly Distance in km
Results for Hidden Valley Grav2d W E Tolerance 2 mGal Density contrast-0.33 g/cc GM-SYS -6 mGal Anomaly Distance in km
Comparison of results Prater W E (Modified from Widmer et al., 2007)
Error • Non-equilibrated spring • Terrain corrections • Elevation error • Inconsistent temperature • User error • Instrument drift
Future Work • Verification of Hidden Valley anomaly • Completion of D’Andrea pkwy line to bolster dataset
Takehome Message • Bolstered NE portion of the Truckee Meadows Basin (TMB) Gravity dataset • Hidden Valley Sub-basin
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