Robertson, Gregory D听1听;听Ge, Shemin听2听;听Cutillo, Paula听3
1听University of Colorado at 麻豆官网
2听University of Colorado at 麻豆官网
3听National Park Service, Water Resource Division
Tectonic deformation in the Great Basin is speculated as one of the possible causes for water level fluctuations observed in Devils Hole, southwestern Nevada. Devils Hole is a large fault cavern located along a 10 mile spring discharge line in a carbonate aquifer, 150 miles west of Las Vegas, Nevada. It is an area of high attention as it provides habitat for an endangered species of fish, Cyprinodon diabolis. The survival of the fish is believed to be dependent upon the water level in Devils Hole.
Tectonic deformation is examined using the volumetric strain field present throughout the Great Basin. Extension in the Devils Hole area is N 65 W at a rate of 8 nanostrain/yr (Wernicke et al., 1998). The carbonate aquifer that provides water to Devils Hole is heterogeneous and anisotropic containing fractures and faults at multiple scales. This preliminary analysis indicates that rates of pressure head fluctuation may be on the order of millimeters per year due to tectonic strain. An external program is used to calculate head changes due to strain present in the Great Basin. Strain is incorporated into the groundwater flow model through imposing these head changes to the initial head at the beginning of each time step in transient MODFLOW simulations.
Wernicke, B., Davis, J., Bennett, R., Elosegui, P., Abolins, M., Brady, R., House, M., Niemi, N., and Snow, J. 1998. Anomalous strain accumulation in the Yucca Mountain area, Nevada. Science, v. 279, p. 2096-2099.