Slip and Dilation Tendency Analysis of the Tuscarora Geothermal Area
Critically stressed fault segments have a relatively high likelihood of acting as fluid flow conduits (Sibson, 1994). As such, the tendency of a fault segment to slip (slip tendency; Ts; Morris et al., 1996) or to dilate (dilation tendency; Td; Ferrill et al., 1999) provides an indication of which faults or fault segments within a geothermal system are critically stressed and therefore likely to transmit geothermal fluids.
The slip tendency of a surface is defined by the ratio of shear stress to normal stress on that surface:
Ts = T / on (Morris et al., 1996).
Dilation tendency is defined by the stress acting normal to a given surface:
Td = (o1-on) / (o1-o3) (Ferrill et al., 1999).
Slip and dilation were calculated using 3DStress (Southwest Research Institute).
Slip and dilation tendency are both unitless ratios of the resolved stresses applied to the fault plane by ambient stress conditions. Values range from a maximum of 1, a fault plane ideally oriented to slip or dilate under ambient stress conditions to zero, a fault plane with no potential to slip or dilate. Slip and dilation tendency values were calculated for each fault in the focus study areas at, McGinness Hills, Neal Hot Springs, Patua, Salt Wells, San Emidio, and Tuscarora on fault traces. As dip is not well constrained or unknown for many faults mapped in within these we made these calculations using the dip for each fault that would yield the maximum slip tendency or dilation tendency. As such, these results should be viewed as maximum tendency of each fault to slip or dilate. The resulting along-fault and fault-to-fault variation in slip or dilation potential is a proxy for along fault and fault-to-fault variation in fluid flow conduit potential.
Stress Magnitudes and directions
Stress field variation within each focus area was approximated based on regional published data and the world stress database (Hickman et al., 2000; Hickman et al., 1998 Robertson-Tait et al., 2004; Hickman and Davatzes, 2010; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012; Moeck et al., 2010; Moos and Ronne, 2010 and Reinecker et al., 2005) as well as local stress information if applicable. For faults within these focus systems we applied either a normal faulting stress regime where the vertical stress (sv) is larger than the maximum horizontal stress (shmax) which is larger than the minimum horizontal stress (sv>shmax>shmin) or strike-slip faulting stress regime where the maximum horizontal stress (shmax) is larger than the vertical stress (sv) which is larger than the minimum horizontal stress (shmax >sv>shmin) depending on the general tectonic province of the system. Based on visual inspection of the limited stress magnitude data in the Great Basin we used magnitudes such that shmin/shmax = .527 and shmin/sv= .46, which are consistent with complete and partial stress field determinations from Desert Peak, Coso, the Fallon area and Dixie valley (Hickman et al., 2000; Hickman et al., 1998 Robertson-Tait et al., 2004; Hickman and Davatzes, 2011; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012).
Slip and dilation tendency for the Tuscarora geothermal field was calculated based on the faults mapped Tuscarora area (Dering, 2013). The Tuscarora area lies in the Basin and Range Province, as such we applied a normal faulting stress regime to the Tuscarora area faults, with a minimum horizontal stress direction oriented 115, based on inspection of local and regional stress determinations, as explained above. Under these stress conditions north-northeast striking, steeply dipping fault segments have the highest dilation tendency, while north-northeast striking 60 degrees dipping fault segments have the highest tendency to slip. Tuscarora is defined by a left-step in a major north- to-north northeast striking, west-dipping range-bounding normal fault system. Faults within the broad step define an anticlinal accommodation zone wherein east-dipping faults mainly occupy western half of the accommodation zone and west-dipping faults lie in the eastern half of the accommodation zone. The geothermal system resides in the axial part of the accommodation, straddling the two fault dip domains. Within the axial part of the accommodation zone several west-dipping, north northeast-striking faults are well oriented for both slip and dilation, including fault strands that are exploited for both production and injection for the Tuscarora geothermal power plant.
NOTE: 'o' is used in this description to represent lowercase sigma.
Citation Formats
TY - DATA
AB - Critically stressed fault segments have a relatively high likelihood of acting as fluid flow conduits (Sibson, 1994). As such, the tendency of a fault segment to slip (slip tendency; Ts; Morris et al., 1996) or to dilate (dilation tendency; Td; Ferrill et al., 1999) provides an indication of which faults or fault segments within a geothermal system are critically stressed and therefore likely to transmit geothermal fluids.
The slip tendency of a surface is defined by the ratio of shear stress to normal stress on that surface:
Ts = T / on (Morris et al., 1996).
Dilation tendency is defined by the stress acting normal to a given surface:
Td = (o1-on) / (o1-o3) (Ferrill et al., 1999).
Slip and dilation were calculated using 3DStress (Southwest Research Institute).
Slip and dilation tendency are both unitless ratios of the resolved stresses applied to the fault plane by ambient stress conditions. Values range from a maximum of 1, a fault plane ideally oriented to slip or dilate under ambient stress conditions to zero, a fault plane with no potential to slip or dilate. Slip and dilation tendency values were calculated for each fault in the focus study areas at, McGinness Hills, Neal Hot Springs, Patua, Salt Wells, San Emidio, and Tuscarora on fault traces. As dip is not well constrained or unknown for many faults mapped in within these we made these calculations using the dip for each fault that would yield the maximum slip tendency or dilation tendency. As such, these results should be viewed as maximum tendency of each fault to slip or dilate. The resulting along-fault and fault-to-fault variation in slip or dilation potential is a proxy for along fault and fault-to-fault variation in fluid flow conduit potential.
Stress Magnitudes and directions
Stress field variation within each focus area was approximated based on regional published data and the world stress database (Hickman et al., 2000; Hickman et al., 1998 Robertson-Tait et al., 2004; Hickman and Davatzes, 2010; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012; Moeck et al., 2010; Moos and Ronne, 2010 and Reinecker et al., 2005) as well as local stress information if applicable. For faults within these focus systems we applied either a normal faulting stress regime where the vertical stress (sv) is larger than the maximum horizontal stress (shmax) which is larger than the minimum horizontal stress (sv>shmax>shmin) or strike-slip faulting stress regime where the maximum horizontal stress (shmax) is larger than the vertical stress (sv) which is larger than the minimum horizontal stress (shmax >sv>shmin) depending on the general tectonic province of the system. Based on visual inspection of the limited stress magnitude data in the Great Basin we used magnitudes such that shmin/shmax = .527 and shmin/sv= .46, which are consistent with complete and partial stress field determinations from Desert Peak, Coso, the Fallon area and Dixie valley (Hickman et al., 2000; Hickman et al., 1998 Robertson-Tait et al., 2004; Hickman and Davatzes, 2011; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012).
Slip and dilation tendency for the Tuscarora geothermal field was calculated based on the faults mapped Tuscarora area (Dering, 2013). The Tuscarora area lies in the Basin and Range Province, as such we applied a normal faulting stress regime to the Tuscarora area faults, with a minimum horizontal stress direction oriented 115, based on inspection of local and regional stress determinations, as explained above. Under these stress conditions north-northeast striking, steeply dipping fault segments have the highest dilation tendency, while north-northeast striking 60 degrees dipping fault segments have the highest tendency to slip. Tuscarora is defined by a left-step in a major north- to-north northeast striking, west-dipping range-bounding normal fault system. Faults within the broad step define an anticlinal accommodation zone wherein east-dipping faults mainly occupy western half of the accommodation zone and west-dipping faults lie in the eastern half of the accommodation zone. The geothermal system resides in the axial part of the accommodation, straddling the two fault dip domains. Within the axial part of the accommodation zone several west-dipping, north northeast-striking faults are well oriented for both slip and dilation, including fault strands that are exploited for both production and injection for the Tuscarora geothermal power plant.
NOTE: 'o' is used in this description to represent lowercase sigma.
AU - E., James
DB - Open Energy Data Initiative (OEDI)
DP - Open EI | National Renewable Energy Laboratory
DO - 10.15121/1136717
KW - geothermal
KW - Tuscarora Geothermal Area
KW - Slip Tendency Analysis
KW - Dilation Tendency Analysis
KW - Slip tendency
KW - dilation tendency
KW - Tuscarora
KW - faulting
KW - faults
KW - fluid flow conduits
KW - stress
KW - ambient stress
KW - shapefile
KW - shape file
KW - GIS
KW - ArcGIS
KW - data
KW - geospatial data
LA - English
DA - 2013/12/31
PY - 2013
PB - University of Nevada
T1 - Slip and Dilation Tendency Analysis of the Tuscarora Geothermal Area
UR - https://doi.org/10.15121/1136717
ER -
E., James. Slip and Dilation Tendency Analysis of the Tuscarora Geothermal Area. University of Nevada, 31 December, 2013, GDR. https://doi.org/10.15121/1136717.
E., J. (2013). Slip and Dilation Tendency Analysis of the Tuscarora Geothermal Area. [Data set]. GDR. University of Nevada. https://doi.org/10.15121/1136717
E., James. Slip and Dilation Tendency Analysis of the Tuscarora Geothermal Area. University of Nevada, December, 31, 2013. Distributed by GDR. https://doi.org/10.15121/1136717
@misc{OEDI_Dataset_6709,
title = {Slip and Dilation Tendency Analysis of the Tuscarora Geothermal Area},
author = {E., James},
abstractNote = {Critically stressed fault segments have a relatively high likelihood of acting as fluid flow conduits (Sibson, 1994). As such, the tendency of a fault segment to slip (slip tendency; Ts; Morris et al., 1996) or to dilate (dilation tendency; Td; Ferrill et al., 1999) provides an indication of which faults or fault segments within a geothermal system are critically stressed and therefore likely to transmit geothermal fluids.
The slip tendency of a surface is defined by the ratio of shear stress to normal stress on that surface:
Ts = T / on (Morris et al., 1996).
Dilation tendency is defined by the stress acting normal to a given surface:
Td = (o1-on) / (o1-o3) (Ferrill et al., 1999).
Slip and dilation were calculated using 3DStress (Southwest Research Institute).
Slip and dilation tendency are both unitless ratios of the resolved stresses applied to the fault plane by ambient stress conditions. Values range from a maximum of 1, a fault plane ideally oriented to slip or dilate under ambient stress conditions to zero, a fault plane with no potential to slip or dilate. Slip and dilation tendency values were calculated for each fault in the focus study areas at, McGinness Hills, Neal Hot Springs, Patua, Salt Wells, San Emidio, and Tuscarora on fault traces. As dip is not well constrained or unknown for many faults mapped in within these we made these calculations using the dip for each fault that would yield the maximum slip tendency or dilation tendency. As such, these results should be viewed as maximum tendency of each fault to slip or dilate. The resulting along-fault and fault-to-fault variation in slip or dilation potential is a proxy for along fault and fault-to-fault variation in fluid flow conduit potential.
Stress Magnitudes and directions
Stress field variation within each focus area was approximated based on regional published data and the world stress database (Hickman et al., 2000; Hickman et al., 1998 Robertson-Tait et al., 2004; Hickman and Davatzes, 2010; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012; Moeck et al., 2010; Moos and Ronne, 2010 and Reinecker et al., 2005) as well as local stress information if applicable. For faults within these focus systems we applied either a normal faulting stress regime where the vertical stress (sv) is larger than the maximum horizontal stress (shmax) which is larger than the minimum horizontal stress (sv>shmax>shmin) or strike-slip faulting stress regime where the maximum horizontal stress (shmax) is larger than the vertical stress (sv) which is larger than the minimum horizontal stress (shmax >sv>shmin) depending on the general tectonic province of the system. Based on visual inspection of the limited stress magnitude data in the Great Basin we used magnitudes such that shmin/shmax = .527 and shmin/sv= .46, which are consistent with complete and partial stress field determinations from Desert Peak, Coso, the Fallon area and Dixie valley (Hickman et al., 2000; Hickman et al., 1998 Robertson-Tait et al., 2004; Hickman and Davatzes, 2011; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012).
Slip and dilation tendency for the Tuscarora geothermal field was calculated based on the faults mapped Tuscarora area (Dering, 2013). The Tuscarora area lies in the Basin and Range Province, as such we applied a normal faulting stress regime to the Tuscarora area faults, with a minimum horizontal stress direction oriented 115, based on inspection of local and regional stress determinations, as explained above. Under these stress conditions north-northeast striking, steeply dipping fault segments have the highest dilation tendency, while north-northeast striking 60 degrees dipping fault segments have the highest tendency to slip. Tuscarora is defined by a left-step in a major north- to-north northeast striking, west-dipping range-bounding normal fault system. Faults within the broad step define an anticlinal accommodation zone wherein east-dipping faults mainly occupy western half of the accommodation zone and west-dipping faults lie in the eastern half of the accommodation zone. The geothermal system resides in the axial part of the accommodation, straddling the two fault dip domains. Within the axial part of the accommodation zone several west-dipping, north northeast-striking faults are well oriented for both slip and dilation, including fault strands that are exploited for both production and injection for the Tuscarora geothermal power plant.
NOTE: 'o' is used in this description to represent lowercase sigma.
},
url = {https://gdr.openei.org/submissions/372},
year = {2013},
howpublished = {GDR, University of Nevada, https://doi.org/10.15121/1136717},
note = {Accessed: 2025-05-04},
doi = {10.15121/1136717}
}
https://dx.doi.org/10.15121/1136717
Details
Data from Dec 31, 2013
Last updated Aug 24, 2021
Submitted Mar 21, 2014
Organization
University of Nevada
Contact
James E. Faulds
775.682.8751
Authors
Original Source
https://gdr.openei.org/submissions/372Research Areas
Keywords
geothermal, Tuscarora Geothermal Area, Slip Tendency Analysis, Dilation Tendency Analysis, Slip tendency, dilation tendency, Tuscarora, faulting, faults, fluid flow conduits, stress, ambient stress, shapefile, shape file, GIS, ArcGIS, data, geospatial dataDOE Project Details
Project Name Recovery Act: Characterizing Structural Controls of EGS-Candidate and Conventional Geothermal Reservoirs in the Great Basin: Developing Successful Exploration Strategies in Extended Terranes
Project Lead Mark Ziegenbein
Project Number EE0002748