Nicholas (Nick) M Beeler
Nick Beeler is a scientist in the Earthquake Science Center.
Science and Products
Filter Total Items: 58
Laboratory observations of fault strength in response to changes in normal stress
Changes in fault normal stress can either inhibit or promote rupture propagation, depending on the fault geometry and on how fault shear strength varies in response to the normal stress change. A better understanding of this dependence will lead to improved earthquake simulation techniques, and ultimately, improved earthquake hazard mitigation efforts. We present the results of new laboratory expe
Authors
Brian D. Kilgore, Julian Lozos, Nicholas M. Beeler, David Oglesby
Constructing constitutive relationships for seismic and aseismic fault slip
For the purpose of modeling natural fault slip, a useful result from an experimental fault mechanics study would be a physically-based constitutive relation that well characterizes all the relevant observations. This report describes an approach for constructing such equations. Where possible the construction intends to identify or, at least, attribute physical processes and contact scale physics
Authors
N.M. Beeler
Constitutive relationships and physical basis of fault strength due to flash heating
We develop a model of fault strength loss resulting from phase change at asperity contacts due to flash heating that considers a distribution of contact sizes and nonsteady state evolution of fault strength with displacement. Laboratory faulting experiments conducted at high sliding velocities, which show dramatic strength reduction below the threshold for bulk melting, are well fit by the model.
Authors
N.M. Beeler, T.E. Tullis, D.L. Goldsby
The instantaneous rate dependence in low temperature laboratory rock friction and rock deformation experiments
[1] Earthquake occurrence probabilities that account for stress transfer and time-dependent failure depend on the product of the effective normal stress and a lab-derived dimensionless coefficient a. This coefficient describes the instantaneous dependence of fault strength on deformation rate, and determines the duration of precursory slip. Although an instantaneous rate dependence is observed for
Authors
N.M. Beeler, T.E. Tullis, A. K. Kronenberg, L.A. Reinen
Inferring earthquake source properties from laboratory observations and the scope of lab contributions to source physics
No abstract available.
Authors
Nicholas M. Beeler
Stress-induced, time-dependent fracture closure at hydrothermal conditions
Time-dependent closure of fractures in quartz was measured in situ at 22–530°C temperature and 0.1-150 MPa water pressure. Unlike previous crack healing and rock permeability studies, in this study, fracture aperture is monitored directly and continuously using a windowed pressure vessel, a long-working-distance microscope, and reflected-light interferometry. Thus the fracture volume and geometry
Authors
N.M. Beeler, S.H. Hickman
Attempting to bridge the gap between laboratory and seismic estimates of fracture energy
To investigate the behavior of the fracture energy associated with expanding the rupture zone of an earthquake, we have used the results of a large-scale, biaxial stick-slip friction experiment to set the parameters of an equivalent dynamic rupture model. This model is determined by matching the fault slip, the static stress drop and the apparent stress. After confirming that the fracture energy a
Authors
A. McGarr, Joe B. Fletcher, N.M. Beeler
On the expected relationships among apparent stress, static stress drop, effective shear fracture energy, and efficiency
We consider expected relationships between apparent stress τa and static stress drop Δτs using a standard energy balance and find τa = Δτs (0.5 - ξ), where ξ is stress overshoot. A simple implementation of this balance is to assume overshoot is constant; then apparent stress should vary linearly with stress drop, consistent with spectral theories (Brune, 1970) and dynamic crack models (Madariaga,
Authors
N.M. Beeler, T.-F. Wong, S.H. Hickman
Why earthquakes correlate weakly with the solid Earth tides: Effects of periodic stress on the rate and probability of earthquake occurrence
We provide an explanation why earthquake occurrence does not correlate well with the daily solid Earth tides. The explanation is derived from analysis of laboratory experiments in which faults are loaded to quasiperiodic failure by the combined action of a constant stressing rate, intended to simulate tectonic loading, and a small sinusoidal stress, analogous to the Earth tides. Event populations
Authors
N.M. Beeler, D. A. Lockner
32 - Rock failure and earthquakes
This chapter summarizes experimental observations and related theoretical developments of faulted and intact rock properties related to earthquake nucleation, failure and dynamic slip. We will be concerned primarily with earthquakes occurring in the brittle crust. Intermediate and deep-focus earthquakes have unique mechanical considerations that are discussed in Section 7. We focus on repeatable l
Authors
David A. Lockner, Nicholas M. Beeler
Stress drop with constant, scale independent seismic efficiency and overshoot
To model dissipated and radiated energy during earthquake stress drop, I calculate dynamic fault slip using a single degree of freedom spring-slider block and a laboratory-based static/kinetic fault strength relation with a dynamic stress drop proportional to effective normal stress. The model is scaled to earthquake size assuming a circular rupture; stiffness varies inversely with rupture radius,
Authors
N.M. Beeler
A simple stick-slip and creep-slip model for repeating earthquakes and its implication for microearthquakes at Parkfield
If repeating earthquakes are represented by circular ruptures, have constant stress drops, and experience no aseismic slip, then their recurrence times should vary with seismic moment as tr ?? Mo1/3. In contrast, the observed variation for small, characteristic repeating earthquakes along a creeping segment of the San Andreas fault at Parkfield (Nadeau and Johnson, 1998) is much weaker. Also, the
Authors
N.M. Beeler, D.L. Lockner, S.H. Hickman
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Filter Total Items: 58
Laboratory observations of fault strength in response to changes in normal stress
Changes in fault normal stress can either inhibit or promote rupture propagation, depending on the fault geometry and on how fault shear strength varies in response to the normal stress change. A better understanding of this dependence will lead to improved earthquake simulation techniques, and ultimately, improved earthquake hazard mitigation efforts. We present the results of new laboratory expeAuthorsBrian D. Kilgore, Julian Lozos, Nicholas M. Beeler, David OglesbyConstructing constitutive relationships for seismic and aseismic fault slip
For the purpose of modeling natural fault slip, a useful result from an experimental fault mechanics study would be a physically-based constitutive relation that well characterizes all the relevant observations. This report describes an approach for constructing such equations. Where possible the construction intends to identify or, at least, attribute physical processes and contact scale physicsAuthorsN.M. BeelerConstitutive relationships and physical basis of fault strength due to flash heating
We develop a model of fault strength loss resulting from phase change at asperity contacts due to flash heating that considers a distribution of contact sizes and nonsteady state evolution of fault strength with displacement. Laboratory faulting experiments conducted at high sliding velocities, which show dramatic strength reduction below the threshold for bulk melting, are well fit by the model.AuthorsN.M. Beeler, T.E. Tullis, D.L. GoldsbyThe instantaneous rate dependence in low temperature laboratory rock friction and rock deformation experiments
[1] Earthquake occurrence probabilities that account for stress transfer and time-dependent failure depend on the product of the effective normal stress and a lab-derived dimensionless coefficient a. This coefficient describes the instantaneous dependence of fault strength on deformation rate, and determines the duration of precursory slip. Although an instantaneous rate dependence is observed forAuthorsN.M. Beeler, T.E. Tullis, A. K. Kronenberg, L.A. ReinenInferring earthquake source properties from laboratory observations and the scope of lab contributions to source physics
No abstract available.AuthorsNicholas M. BeelerStress-induced, time-dependent fracture closure at hydrothermal conditions
Time-dependent closure of fractures in quartz was measured in situ at 22–530°C temperature and 0.1-150 MPa water pressure. Unlike previous crack healing and rock permeability studies, in this study, fracture aperture is monitored directly and continuously using a windowed pressure vessel, a long-working-distance microscope, and reflected-light interferometry. Thus the fracture volume and geometryAuthorsN.M. Beeler, S.H. HickmanAttempting to bridge the gap between laboratory and seismic estimates of fracture energy
To investigate the behavior of the fracture energy associated with expanding the rupture zone of an earthquake, we have used the results of a large-scale, biaxial stick-slip friction experiment to set the parameters of an equivalent dynamic rupture model. This model is determined by matching the fault slip, the static stress drop and the apparent stress. After confirming that the fracture energy aAuthorsA. McGarr, Joe B. Fletcher, N.M. BeelerOn the expected relationships among apparent stress, static stress drop, effective shear fracture energy, and efficiency
We consider expected relationships between apparent stress τa and static stress drop Δτs using a standard energy balance and find τa = Δτs (0.5 - ξ), where ξ is stress overshoot. A simple implementation of this balance is to assume overshoot is constant; then apparent stress should vary linearly with stress drop, consistent with spectral theories (Brune, 1970) and dynamic crack models (Madariaga,AuthorsN.M. Beeler, T.-F. Wong, S.H. HickmanWhy earthquakes correlate weakly with the solid Earth tides: Effects of periodic stress on the rate and probability of earthquake occurrence
We provide an explanation why earthquake occurrence does not correlate well with the daily solid Earth tides. The explanation is derived from analysis of laboratory experiments in which faults are loaded to quasiperiodic failure by the combined action of a constant stressing rate, intended to simulate tectonic loading, and a small sinusoidal stress, analogous to the Earth tides. Event populationsAuthorsN.M. Beeler, D. A. Lockner32 - Rock failure and earthquakes
This chapter summarizes experimental observations and related theoretical developments of faulted and intact rock properties related to earthquake nucleation, failure and dynamic slip. We will be concerned primarily with earthquakes occurring in the brittle crust. Intermediate and deep-focus earthquakes have unique mechanical considerations that are discussed in Section 7. We focus on repeatable lAuthorsDavid A. Lockner, Nicholas M. BeelerStress drop with constant, scale independent seismic efficiency and overshoot
To model dissipated and radiated energy during earthquake stress drop, I calculate dynamic fault slip using a single degree of freedom spring-slider block and a laboratory-based static/kinetic fault strength relation with a dynamic stress drop proportional to effective normal stress. The model is scaled to earthquake size assuming a circular rupture; stiffness varies inversely with rupture radius,AuthorsN.M. BeelerA simple stick-slip and creep-slip model for repeating earthquakes and its implication for microearthquakes at Parkfield
If repeating earthquakes are represented by circular ruptures, have constant stress drops, and experience no aseismic slip, then their recurrence times should vary with seismic moment as tr ?? Mo1/3. In contrast, the observed variation for small, characteristic repeating earthquakes along a creeping segment of the San Andreas fault at Parkfield (Nadeau and Johnson, 1998) is much weaker. Also, theAuthorsN.M. Beeler, D.L. Lockner, S.H. Hickman