Nonlinear fault damage zone scaling revealed through analog modeling

Fault damage zones strongly influence fluid flow and seismogenic behavior of faults and are thought to scale linearly with fault displacement until reaching a threshold thickness. Using analog modeling with different frictional layer thicknesses, we investigate damage zone dynamic evolution during normal fault growth. We show that experimental damage zone growth with displacement is not linear but progressively tends toward a threshold thickness, being larger in the thicker models. This threshold thickness increases significantly at fault segment relay zones. As the thickness threshold is approached, the failure mode progressively transitions from dilational shear to isochoric shear. This process affects the whole layer thickness and develops as a consequence of fault segment linkage as inferred in nature when the fault matures. These findings suggest that fault damage zone widths are limited both by different scales of mechanical unit thickness and the evolution of failure modes, ultimately controlled in nature by lithology and deformation conditions.

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Lateral propagation of the surface trace of the South Alkyonides normal fault segment, central Greece: its impact on models of fault growth and displacement–length relationships

Journal of Structural Geology ◽

10.1016/s0191-8141(99)00049-8 ◽

1999 ◽

Vol 21 (6) ◽

pp. 635-652 ◽

Cited By ~ 59

Author(s):

Nigel C Morewood ◽

Gerald P Roberts

Keyword(s):

Normal Fault ◽

The South ◽

Fault Segment ◽

Central Greece ◽

Fault Growth ◽

Lateral Propagation

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Supplemental Material: Nonlinear fault damage zone scaling revealed through analog modeling

10.1130/geol.s.14390651 ◽

2021 ◽

Author(s):

Sylvain Mayolle ◽

et al.

Keyword(s):

Damage Zone ◽

Volumetric Strain ◽

Gradient Field ◽

Displacement Gradient ◽

Strain Fields ◽

Additional Information ◽

Parametric Data ◽

Analog Modeling ◽

Fault Damage Zone ◽

Material Nonlinear

(1) Movie and description of displacement gradient field evolution; (2) movie of strain fields evolution; (3) cummulative displacement field; (4) displacement gradient profiles through faults; (5) volumetric strain profiles through faults; (6) mechanical properties of the frictional layer; (7) images and parametric data of all the models; (8) a graph of all the measured D-T data; and additional information on the method and scaling to nature.<br>

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Episodic fluid flow in an active fault

Geology ◽

10.1130/g46254.1 ◽

2019 ◽

Vol 47 (10) ◽

pp. 938-942 ◽

Cited By ~ 8

Author(s):

Sarah Louis ◽

Elco Luijendijk ◽

István Dunkl ◽

Mark Person

Keyword(s):

Fluid Flow ◽

Numerical Models ◽

Damage Zone ◽

Normal Fault ◽

Geothermal Gradient ◽

Hydrothermal Activity ◽

The Past ◽

Discharge Rates ◽

Fault Damage Zone ◽

Wide Zone

Abstract We present a reconstruction of episodic fluid flow over the past ∼250 k.y. along the Malpais normal fault, which hosts the Beowawe hydrothermal system (Nevada, USA), using a novel combination of the apatite (U-Th)/He (AHe) thermochronometer and a model of the thermal effects of fluid flow. Samples show partial resetting of the AHe thermochronometer in a 40-m-wide zone around the fault. Numerical models using current fluid temperatures and discharge rates indicate that fluid flow events lasting 2 k.y. or more lead to fully reset samples. Episodic fluid pulses lasting 1 k.y. result in partially reset samples, with 30–40 individual fluid pulses required to match the data. Episodic fluid flow is also supported by an overturned geothermal gradient in a borehole that crosses the fault, and by breaks in stable isotope trends in hydrothermal sinter deposits that coincide with two independently dated earthquakes in the past 20 k.y. This suggests a system where fluid flow is triggered by repeated seismic activity, and that seals itself over ∼1 k.y. due to the formation of clays and silicates in the fault damage zone. Hydrothermal activity is younger than the 6–10 Ma age of the fault, which means that deep (∼5 km) fluid flow was initiated only after a large part of the 230 m of fault offset had taken place.

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Supplemental Material: Nonlinear fault damage zone scaling revealed through analog modeling

10.1130/geol.s.14390651.v1 ◽

2021 ◽

Author(s):

Sylvain Mayolle ◽

et al.

Keyword(s):

Damage Zone ◽

Volumetric Strain ◽

Gradient Field ◽

Displacement Gradient ◽

Strain Fields ◽

Additional Information ◽

Parametric Data ◽

Analog Modeling ◽

Fault Damage Zone ◽

Material Nonlinear

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Spatiotemporal history of fault–fluid interaction in the Hurricane fault, western USA

Solid Earth ◽

10.5194/se-11-1969-2020 ◽

2020 ◽

Vol 11 (6) ◽

pp. 1969-1985

Author(s):

Jace M. Koger ◽

Dennis L. Newell

Keyword(s):

Damage Zone ◽

Carbon Sources ◽

Normal Fault ◽

Western Usa ◽

Calcite Vein ◽

Regional Flow ◽

Fault Strength ◽

History Of ◽

Fault Damage Zone ◽

Fluid Interaction

Abstract. The Hurricane fault is a ∼250 km long, west-dipping, segmented normal fault zone located along the transition between the Colorado Plateau and the Basin and Range tectonic provinces in the western USA. Extensive evidence of fault–fluid interaction includes calcite mineralization and veining. Calcite vein carbon (δ13CVPDB) and oxygen (δ18OVPDB) stable isotope ratios range from −4.5 ‰ to 3.8 ‰ and from −22.1 ‰ to −1.1 ‰, respectively. Fluid inclusion microthermometry constrains paleofluid temperatures and salinities from 45 to 160 ∘C and from 1.4 wt % to 11.0 wt % as NaCl, respectively. These data suggest mixing between two primary fluid sources, including infiltrating meteoric water (70±10 ∘C, ∼1.5 wt % NaCl, δ18OVSMOW ∼-10 ‰) and sedimentary brine (100±25 ∘C, ∼11 wt % NaCl, δ18OVSMOW ∼ 5 ‰). Interpreted carbon sources include crustal- or magmatic-derived CO2, carbonate bedrock, and hydrocarbons. Uranium–thorium (U–Th) dates from five calcite vein samples indicate punctuated fluid flow and fracture healing at 539±10.8 (1σ), 287.9±5.8, 86.2±1.7, and 86.0±0.2 ka in the upper 500 m of the crust. Collectively, data predominantly from the footwall damage zone imply that the Hurricane fault imparts a strong influence on the regional flow of crustal fluids and that the formation of veins in the shallow parts of the fault damage zone has important implications for the evolution of fault strength and permeability.

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Spatiotemporal history of fluid-fault interaction in the Hurricane fault zone, western USA

10.5194/se-2020-69 ◽

2020 ◽

Author(s):

Jace M. Koger ◽

Dennis L. Newell

Keyword(s):

Damage Zone ◽

Carbon Sources ◽

Normal Fault ◽

Fault Interaction ◽

Calcite Vein ◽

Regional Flow ◽

Fault Strength ◽

Primary Fluid ◽

History Of ◽

Fault Damage Zone

Abstract. The Hurricane Fault is a ~250-km-long, west-dipping normal fault located along the transition between the Colorado Plateau and Basin and Range tectonic provinces in the western U.S. Extensive evidence of fluid-fault interaction, including calcite mineralization and veining, occur in the footwall damage zone. Calcite vein carbon (δ13CVPDB) and oxygen (δ18OVPDB) stable isotope ratios range from −4.5 to 3.8 ‰ and −22.1 to −1.1 ‰, respectively. Fluid inclusion microthermometry constrain paleofluid temperatures and salinities from 45–160 °C and 1.4–11.0 wt % as NaCl, respectively. These data identify mixing between two primary fluid sources including infiltrating meteoric groundwater (70 ± 10 °C, ~1.5 wt % NaCl, δ18OSMOW ~−10 ‰) and sedimentary brine (100 ± 25 °C, ~11 wt % NaCl, δ18OSMOW ~5 ‰). Interpreted carbon sources include crustal- or magmatic-derived CO2, carbonate bedrock, and hydrocarbons. U-Th dates from 5 calcite vein samples indicates punctuated fluid-flow and fracture healing at 539 ± 10.8, 287.9 ± 5.8, 86.2 ± 1.7, and 86.0 ± 0.2 ka in the upper 300 m of the crust. Collectively, the data imply that the Hurricane Fault imparts a strong influence on regional flow of crustal fluids, and that the formation of veins in the shallow parts of the fault damage zone has important implications for the evolution of fault strength and permeability.

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