Geostatistical evaluation of permeability in an active fault zone

Abstract

[1] This study presents a description of permeability in an active fault zone located in the Great Basin extensional province. The fault hydraulic structure is inferred from geostatistical analysis of temperatures in 143 geothermal springs, located along a fault trace in the Alvord Basin of southeast Oregon. Based on this analysis, we conclude that the fault zone is predominately low permeability, interspersed with relatively few, spatially-discrete, highpermeability channels. The conceptual model presented is in agreement with the findings of other investigators, but extends their work by offering a representation of fault properties at the tens to hundreds of meters scale.

Field observation of fluid circulation patterns in a normal fault system

“…Furthermore, faults have been shown to be highly heterogeneous [Jourde et al, 2002;Fairley et al, 2003;Fairley and Hinds, 2004;Kato et al, 2004], and their properties may change over time [Smith et al, 1990;Caine et al, 1996;Curewitz and Karson, 1997;Evans et al, 1997].…”

“…[2] Faults have been shown to act as barriers to subsurface fluid flow [Antonellini and Aydin, 1994;Mayo et al, 2003], conduits [Barton et al, 1995;Curewitz and Karson, 1997;Fairley et al, 2003], or a combination of barrier and conduit [Smith et al, 1990;Caine et al, 1996;Evans et al, 1997;Jourde et al, 2002], depending on the amount of fracturing and cataclasis, the extent of alteration and precipitation, composition of the protolith, and the direction of flow with respect to the fault plane. Furthermore, faults have been shown to be highly heterogeneous [Jourde et al, 2002;Fairley et al, 2003;Fairley and Hinds, 2004;Kato et al, 2004], and their properties may change over time [Smith et al, 1990;Caine et al, 1996;Curewitz and Karson, 1997;Evans et al, 1997].…”

Probability-based classifications for spatially characterizing the water temperatures and discharge rates of hot springs in the Tatun Volcanic Region, Taiwan

“…Additionally, Ferguson and Grasby (2011) showed that a clear understanding of the water temperatures and discharge rates of springs facilitates assessing and using geothermal resources. Moreover, spring water temperatures may indirectly influence the permeability of spring channels and discharge because advective heat transport is increased in areas with increased fracturing (Fairley et al 2003;Anderson and Fairley 2008). However, previous investigations have seldom classified and examined the spatial characteristics of the water temperatures and discharge rates of springs.…”

“…1 Map of the Tatun Volcanic Region probabilities of specific spring water temperatures occurring in the Euganean geothermal area and discussed the relationship between spring water temperature and use. Fairley et al (2003) conducted geostatistical simulations of spring water temperatures in an active fault zone and explored the spatial heterogeneity of that area. Anderson and Fairley (2008) temperatures and classified a fault-controlled spring area into low-, moderate-, and high-temperature domains according to the estimated probabilities.…”

Imaging complex structure in shallow seismic‐reflection data using pre‐stack depth migration

“…Based on gravity data, topographic expression, and the linear trend of the series of springs that define the BLHS, previous workers have inferred that the BLHS is controlled by a north-south-trending, midbasin fault ͑Cleary et al Fairley et al, 2003͒. We are using a number of geophysical techniques, including gravity, magnetics, and time-domain electromagnetics, to characterize the BLHS at scales ranging from 10 1 to 10 3 m ͑Hess et al, 2004͒.…”