HR: 09:30h
AN: H51B-07    [PDF]
TI: A Quantitative Assessment of the Influence of Structural Setting on Fault Hydraulic Property Distributions
AU: * Fairley, J P
EM: jfairley@uidaho.edu
AF: Department of Geological Sciences, University of Idaho, Moscow, ID 83844-3022 United States
AU: Heffner, J
EM: j_heffner@yahoo.com
AF: Department of Geological Sciences, University of Idaho, Moscow, ID 83844-3022 United States
AU: Hinds, J J
EM: jhinds@uidaho.edu
AF: Department of Geological Sciences, University of Idaho, Moscow, ID 83844-3022 United States
AB: It is generally agreed that faults are an important control on groundwater flow, but relatively little work has been done to link structural setting with fault hydraulic properties at a level of detail appropriate for field-scale numerical modeling. The present study examines the influence of the structural setting on fault permeability by comparing spring temperature distributions from two geothermal areas in the Alvord Basin of southwest Oregon. Geothermal springs near the Borax Lake site occur along the trace of a normal fault, and appear to have developed a quasi-steady state spatial distribution. Geothermal vents in the Mickey Hot Springs area occur in a restricted zone between two fault splays; mean spring temperature at Mickey Hot Springs is significantly higher than at Borax Lake, and the center of spring activity shows evidence of migration with time. A geostatistical analysis of spring temperatures is used to quantify the differences in permeability distributions between the two sites, and illustrates the importance of including structural data in the development of realistic hydraulic property sets for numerical models of groundwater flow at fault-controlled sites.
UR: http://www.uidaho.edu/biogeochemistry
DE: 1829 Groundwater hydrology
DE: 1869 Stochastic processes
DE: 8010 Fractures and faults
DE: 8045 Role of fluids
DE: 8135 Hydrothermal systems (8424)
SC: Hydrology [H]
MN: 2003 Fall Meeting