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Friction and Permeability Evolution of Fracutres and Faults During Static Repose and Dynamic Reactivation.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Friction and Permeability Evolution of Fracutres and Faults During Static Repose and Dynamic Reactivation./
作者:	Im, Kyungjae.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2019,
面頁冊數:	161 p.
附註:	Source: Dissertations Abstracts International, Volume: 80-12, Section: B.
Contained By:	Dissertations Abstracts International80-12B.
標題:	Geophysics. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=13917918
ISBN:	9781392318515

Friction and Permeability Evolution of Fracutres and Faults During Static Repose and Dynamic Reactivation.
Im, Kyungjae.

Friction and Permeability Evolution of Fracutres and Faults During Static Repose and Dynamic Reactivation. - Ann Arbor : ProQuest Dissertations & Theses, 2019 - 161 p.

Source: Dissertations Abstracts International, Volume: 80-12, Section: B.

Thesis (Ph.D.)--The Pennsylvania State University, 2019.

This item must not be added to any third party search indexes.

The co-evolution of fault/fracture friction and permeability represent important science/engineering challenges impacting natural and engineered systems. Friction directly controls the characteristics of natural fault slip, including inter-seismic healing, slow creep and earthquake rupture. Permeability evolution during fault slip and repose illuminates our understanding of perturbations to the earthquake-modulated natural hydraulic system and of subsurface engineering in recovering both shale gas and geothermal energy and in the safe subsurface sequestration of CO2. However, mechanisms controlling the evolution of friction and permeability during slow slip, fast rupture and inter-event repose are not clearly understood. For instance, the evolution of stick-slip amplitudes and recurrence, the role of inertia and its influence on frictional stability and the interdependence of these processes remain unclear. Furthermore, mechanisms of permeability evolution during the earthquake cycle (repose through rupture) are also poorly understood since they are influenced in a complex way by chemo-mechanical effects such as elastic/plastic compaction, shear comminution, mechanical dilation, pressure solution and stress corrosion. In this study, we explore fracture friction and permeability evolution during static and dynamic reactivation using both numerical and experimental approaches. This is described in the four chapters of this dissertation.Chapters 1 and 2 explore inter-seismic frictional healing, co-seismic stress drop and the role of inertia on unstable sliding.In Chapter 1, we investigate the direct linkage between stick-slip evolution and rate-and-state friction parameters via a novel numerical method. We use RSF (rate and state friction) laws to demonstrate that the back-projected time of null-healing intrinsically scales with the initial frictional state θi. We explore this behavior and its implications for: 1) the short-term cutoff time of frictional healing and 2) the connection between healing rates derived from stick-slip sliding versus slide-hold-slide tests. We use a novel, continuous solution of RSF for a one-dimensional spring-slider system with inertia. The numerical solution continuously traces frictional state evolution (and healing) and shows that stick-slip cut-off time also scales with frictional state at the conclusion of the dynamic slip process θi (=Dc/Vpeak). This numerical investigation on the origins of stick slip response is verified by comparing laboratory data for a range of peak slip velocities. Slower slip motions yield lesser magnitude of friction drop at a given time due to higher frictional state at the end of each slip event. Our results provide insight on the origin of log-linear stick slip evolution and suggest an approach to estimating the critical slip distance on faults that exhibit gradual accelerations, such as for slow earthquakes.In Chapter 2, unstable frictional slip motions are investigated with a rate and state friction law across the transition from quasi-static (slowly loaded) slip to dynamic slip, dominated by inertia. Using a novel numerical method, we conduct simulations to investigate the roles of inertial and quasistatic factors of the critical stiffness defining the transition to instability, Kc. Our simulations confirm theoretical estimates of Kc, which is dependent on mass and velocity. Furthermore, we show that unstable slip motion has two distinct dynamic regimes with characteristic limit cycles: (i) stick-slip motions in the quasistatic (slowly loaded) regime and (ii) quasi-harmonic oscillations in the dynamic (fast loaded) regime. Simulation results show that the regimes are divided by the frictional instability coefficient, η = MV2/σaDc and stiffness of the system K. The quasi-static regime is governed by the ratio K/Kc and both the period and magnitude of stick-slip cycles decrease with increasing loading rate. In the dynamic regime, slip occurs in harmonic limit cycles, the frequency of which increases with loading velocity to a limit set by the natural frequency of the system. Our results illuminate the origin of the broad spectrum of slip behaviors observed for systems ranging from manufacturing equipment to automobiles and tectonic faults, with particular focus on the role of elasto-frictional coupling in dictating the transition from slow slip to dynamic instability. We highlight distinct characteristics of friction-induced slip motions (stick-slip and friction-induced vibration) and show that the dynamic frictional instability coefficient (η) is a key parameter that both defines the potential for instability and determines the dynamic characteristics of instability.Chapters 3 and 4 experimentally explore the evolution of fracture transport properties with concurrent measurement of friction and permeability during static and dynamic reactivation.In Chapter 3, we show that the evolution of permeability on fractures and faults during the full earthquake cycle is sensitive to sealing during the repose phase. We explore the combined effect of static loading followed by fracture reactivation on permeability evolution via slide-hold-slide experiments. During the hold periods, permeability exhibits a slow but continuous reduction. The permeability decay is consistent with power law compaction of the aperture coupled with cubic law flow. With increasing hold periods, permeability evolves following reactivation from net reduction to net increase with the magnitude of the permeability change dependent on the hold period. This implies that the tight interlocking of asperities during inter-seismic repose primes the fault for permeability enhancement following reactivation. The inferred mechanism is via shear dilation with the probable involvement of unclogging. This result identifies that pre-slip sealing during repose is an essential component in the cyclic permeability evolution throughout the seismic cycle.The cyclic growth and decay of permeability is further investigated in Chapter 4. We conduct slide-hold-slide experiments that are constrained by measurements of fracture normal deformation and optical surface profilometry. Overall, we observe continuous permeability decay during repose periods (holds) and significant permeability enhancement during reactivation (slide). The permeability decay is accompanied by fault normal compaction. Both hydraulic aperture change (Δbh) and measured compaction (Δbs) are consistent with time dependent power law closure with a power exponent of ~0.2-0.4. These dual compaction magnitudes are positively correlated but Δbh>Δbs in late stage holds. Permeability enhancement during shear reactivation is typically also accompanied by fault dilation. However, we also observe some cases where changes in hydraulic aperture and permeability decouple from the measured normal deformation, conceivably driven by mobilization of wear products and influenced by the development of flow bottlenecks. Pre- and post-test surface profiles show that the surface topography of the fractures is planed-down by shear removal. However, the flattened surfaces retain small scale roughness with mating and intergrowth anticipated to develop during the observed slow compaction. Flow simulations, constrained by the surface topography and measured deformation, indicate that small-scale roughness may control permeability at flow bottlenecks within a dominant flow channel. These results suggest cycles of permeability creation and destruction are an intrinsic component of the natural hydraulic system present in faults and fractures and provide an improved mechanistic understanding of the evolution of permeability during fault repose and reactivation.

ISBN: 9781392318515Subjects--Topical Terms:

535228
Geophysics.

Friction and Permeability Evolution of Fracutres and Faults During Static Repose and Dynamic Reactivation.
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500 $a Source: Dissertations Abstracts International, Volume: 80-12, Section: B.
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500 $a Advisor: Elsworth, Derek.
502 $a Thesis (Ph.D.)--The Pennsylvania State University, 2019.
506 $a This item must not be added to any third party search indexes.
506 $a This item must not be sold to any third party vendors.
520 $a The co-evolution of fault/fracture friction and permeability represent important science/engineering challenges impacting natural and engineered systems. Friction directly controls the characteristics of natural fault slip, including inter-seismic healing, slow creep and earthquake rupture. Permeability evolution during fault slip and repose illuminates our understanding of perturbations to the earthquake-modulated natural hydraulic system and of subsurface engineering in recovering both shale gas and geothermal energy and in the safe subsurface sequestration of CO2. However, mechanisms controlling the evolution of friction and permeability during slow slip, fast rupture and inter-event repose are not clearly understood. For instance, the evolution of stick-slip amplitudes and recurrence, the role of inertia and its influence on frictional stability and the interdependence of these processes remain unclear. Furthermore, mechanisms of permeability evolution during the earthquake cycle (repose through rupture) are also poorly understood since they are influenced in a complex way by chemo-mechanical effects such as elastic/plastic compaction, shear comminution, mechanical dilation, pressure solution and stress corrosion. In this study, we explore fracture friction and permeability evolution during static and dynamic reactivation using both numerical and experimental approaches. This is described in the four chapters of this dissertation.Chapters 1 and 2 explore inter-seismic frictional healing, co-seismic stress drop and the role of inertia on unstable sliding.In Chapter 1, we investigate the direct linkage between stick-slip evolution and rate-and-state friction parameters via a novel numerical method. We use RSF (rate and state friction) laws to demonstrate that the back-projected time of null-healing intrinsically scales with the initial frictional state θi. We explore this behavior and its implications for: 1) the short-term cutoff time of frictional healing and 2) the connection between healing rates derived from stick-slip sliding versus slide-hold-slide tests. We use a novel, continuous solution of RSF for a one-dimensional spring-slider system with inertia. The numerical solution continuously traces frictional state evolution (and healing) and shows that stick-slip cut-off time also scales with frictional state at the conclusion of the dynamic slip process θi (=Dc/Vpeak). This numerical investigation on the origins of stick slip response is verified by comparing laboratory data for a range of peak slip velocities. Slower slip motions yield lesser magnitude of friction drop at a given time due to higher frictional state at the end of each slip event. Our results provide insight on the origin of log-linear stick slip evolution and suggest an approach to estimating the critical slip distance on faults that exhibit gradual accelerations, such as for slow earthquakes.In Chapter 2, unstable frictional slip motions are investigated with a rate and state friction law across the transition from quasi-static (slowly loaded) slip to dynamic slip, dominated by inertia. Using a novel numerical method, we conduct simulations to investigate the roles of inertial and quasistatic factors of the critical stiffness defining the transition to instability, Kc. Our simulations confirm theoretical estimates of Kc, which is dependent on mass and velocity. Furthermore, we show that unstable slip motion has two distinct dynamic regimes with characteristic limit cycles: (i) stick-slip motions in the quasistatic (slowly loaded) regime and (ii) quasi-harmonic oscillations in the dynamic (fast loaded) regime. Simulation results show that the regimes are divided by the frictional instability coefficient, η = MV2/σaDc and stiffness of the system K. The quasi-static regime is governed by the ratio K/Kc and both the period and magnitude of stick-slip cycles decrease with increasing loading rate. In the dynamic regime, slip occurs in harmonic limit cycles, the frequency of which increases with loading velocity to a limit set by the natural frequency of the system. Our results illuminate the origin of the broad spectrum of slip behaviors observed for systems ranging from manufacturing equipment to automobiles and tectonic faults, with particular focus on the role of elasto-frictional coupling in dictating the transition from slow slip to dynamic instability. We highlight distinct characteristics of friction-induced slip motions (stick-slip and friction-induced vibration) and show that the dynamic frictional instability coefficient (η) is a key parameter that both defines the potential for instability and determines the dynamic characteristics of instability.Chapters 3 and 4 experimentally explore the evolution of fracture transport properties with concurrent measurement of friction and permeability during static and dynamic reactivation.In Chapter 3, we show that the evolution of permeability on fractures and faults during the full earthquake cycle is sensitive to sealing during the repose phase. We explore the combined effect of static loading followed by fracture reactivation on permeability evolution via slide-hold-slide experiments. During the hold periods, permeability exhibits a slow but continuous reduction. The permeability decay is consistent with power law compaction of the aperture coupled with cubic law flow. With increasing hold periods, permeability evolves following reactivation from net reduction to net increase with the magnitude of the permeability change dependent on the hold period. This implies that the tight interlocking of asperities during inter-seismic repose primes the fault for permeability enhancement following reactivation. The inferred mechanism is via shear dilation with the probable involvement of unclogging. This result identifies that pre-slip sealing during repose is an essential component in the cyclic permeability evolution throughout the seismic cycle.The cyclic growth and decay of permeability is further investigated in Chapter 4. We conduct slide-hold-slide experiments that are constrained by measurements of fracture normal deformation and optical surface profilometry. Overall, we observe continuous permeability decay during repose periods (holds) and significant permeability enhancement during reactivation (slide). The permeability decay is accompanied by fault normal compaction. Both hydraulic aperture change (Δbh) and measured compaction (Δbs) are consistent with time dependent power law closure with a power exponent of ~0.2-0.4. These dual compaction magnitudes are positively correlated but Δbh>Δbs in late stage holds. Permeability enhancement during shear reactivation is typically also accompanied by fault dilation. However, we also observe some cases where changes in hydraulic aperture and permeability decouple from the measured normal deformation, conceivably driven by mobilization of wear products and influenced by the development of flow bottlenecks. Pre- and post-test surface profiles show that the surface topography of the fractures is planed-down by shear removal. However, the flattened surfaces retain small scale roughness with mating and intergrowth anticipated to develop during the observed slow compaction. Flow simulations, constrained by the surface topography and measured deformation, indicate that small-scale roughness may control permeability at flow bottlenecks within a dominant flow channel. These results suggest cycles of permeability creation and destruction are an intrinsic component of the natural hydraulic system present in faults and fractures and provide an improved mechanistic understanding of the evolution of permeability during fault repose and reactivation.
590 $a School code: 0176.
650 4 $a Geophysics. $3 535228
650 4 $a Hydrologic sciences. $3 3168407
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710 2 $a The Pennsylvania State University. $b Energy and Mineral Engineering. $3 2105124
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