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Nicholas (Nick) M Beeler

Nick Beeler is a scientist in the Earthquake Science Center.

Science and Products

Filter Total Items: 48

The evolution of rock friction is more sensitive to slip than elapsed time, even at near-zero slip rates

For many decades, frictional strength increase at low slip rates has been ascribed to time-dependent contact-area growth across the sliding interface. As a result, phenomenological models that correctly predict contact-area growth, as observed in laboratory experiments, have also been widely assumed to be appropriate descriptors of frictional strength evolution. We present experiments that impose
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Natural Hazards, Earthquake Hazards, Earthquake Science Center

Apparent age dependence of the fault weakening distance in rock friction

During rock friction experiments at large displacement, room temperature and humidity, and following a hold test, the fracture energy increases approximately as the square of the logarithm of hold duration. While it's been long known that failure strength increases with log hold time, here the slip weakening distance, dh, also increases. The weakening distance increase is large, hundreds of percen
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Natural Hazards, Earthquake Hazards, Earthquake Science Center

Strength recovery and sealing under hydrothermal conditions

While there is significant evidence for healing in natural faults, geothermal reservoirs, and lab experiments, the thermal, hydraulic, mechanical, and chemical interactions that influence healing are poorly understood. We present preliminary results of triaxial slide-hold-slide experiments to constrain rates and mechanisms of healing. Experiments were conducted on gouge composed of Westerly granit
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Natural Hazards, Earthquake Hazards, Earthquake Science Center

Teleseismic waves reveal anisotropic poroelastic response of wastewater disposal reservoir

Connecting earthquake nucleation in basement rock to fluid injection in basal, sedimentary reservoirs, depends heavily on choices related to the poroelastic properties of the fluid-rock system, thermo-chemical effects notwithstanding. Direct constraints on these parameters outside of laboratory settings are rare, and it is commonly assumed that the rock layers are isotropic. With the Arbuckle wast
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Natural Hazards, Earthquake Hazards, Earthquake Science Center

Evolution of fluid transmissivity and strength recovery of shear fractures under hydrothermal conditions

Geothermal systems rely on the presence of long-lived and high-volume, permeable fracture systems. The creation, reactivation, and sustainability of these systems depend on complex coupling among thermal, hydraulic, mechanical, and chemical (THMC) processes occurring in geothermal reservoirs. In part due to a paucity of experimental data, the evolution of fractures at geothermal conditions in resp
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Natural Hazards, Earthquake Hazards, Earthquake Science Center

Characterizing fault roughness—Are faults rougher at long or short wavelengths?

Changes in fault roughness with scale, “scaling,” is the topic of this report; changes are considered using a general power law relation between some measure of surface height, H, and another of length, L, H=kLn, where k is a constant and n is an exponent that characterizes the scaling. Extensive profile measurements of natural fault surfaces show that the ratio of average surface height to profil
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Natural Hazards, Earthquake Hazards, Earthquake Science Center

Near-fault velocity spectra from laboratory failures and their relation to natural ground motion

We compared near-fault velocity spectra recorded during laboratory experiments to that of natural earthquakes. We fractured crystalline rock samples at room temperature and intermediate confining pressure (50 MPa). Subsequent slip events were generated on the fracture surfaces under higher confinement (300 MPa). Velocity spectra from rock fracture resemble the inverse frequency (1/f) decay of natu
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Natural Hazards, Earthquake Hazards, Earthquake Science Center

Conversion of wet glass to melt at lower seismogenic zone conditions: Implications for pseudotachylyte creep

Coseismic frictional melting and the production of quenched glass called pseudotachylyte is a recurring process during earthquakes. To investigate how glassy materials affect the postseismic strength and stability of faults, obsidian gouges were sheared under dry and wet conditions from 200°C to 300°C at ~150 MPa effective normal stress. Dry glass exhibited a brittle rheology at all conditions tes
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Natural Hazards, Earthquake Hazards, Earthquake Science Center

Rock friction under variable normal stress

This study is to determine the detailed response of shear strength and other fault properties to changes in normal stress at room temperature using dry initially bare rock surfaces of granite at normal stresses between 5 and 7 MPa. Rapid normal stress changes result in gradual, approximately exponential changes in shear resistance with fault slip. The characteristic length of the exponential chang
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Natural Hazards, Earthquake Hazards, Earthquake Science Center

The transition from frictional sliding to shear melting in laboratory stick-slip experiments

No abstract available
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Natural Hazards, Earthquake Hazards, Earthquake Science Center

Laboratory constraints on models of earthquake recurrence

In this study, rock friction ‘stick-slip’ experiments are used to develop constraints on models of earthquake recurrence. Constant-rate loading of bare rock surfaces in high quality experiments produces stick-slip recurrence that is periodic at least to second order. When the loading rate is varied, recurrence is approximately inversely proportional to loading rate. These laboratory events initiat
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Natural Hazards, Earthquake Hazards, Earthquake Science Center

Earthquake source properties from instrumented laboratory stick-slip

Stick-slip experiments were performed to determine the influence of the testing apparatus on source properties, develop methods to relate stick-slip to natural earthquakes and examine the hypothesis of McGarr [2012] that the product of stiffness, k, and slip duration, Δt, is scale-independent and the same order as for earthquakes. The experiments use the double-direct shear geometry, Sierra White
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Natural Hazards, Earthquake Hazards, Earthquake Science Center
link
map of Alaska area with 2020-2021 earthquakes, showing circles for earthquake locations

External Grants - Overview

The U.S. Geological Survey (USGS) provides support for research that will assist in achieving the goals of the Earthquake Hazards Program. The goal is to mitigate earthquake losses that can occur in many parts of the nation by providing earth science data and assessments essential for land-use planning, engineering design, and emergency preparedness decisions.
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Natural Hazards, Earthquake Hazards
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External Grants - Overview

The U.S. Geological Survey (USGS) provides support for research that will assist in achieving the goals of the Earthquake Hazards Program. The goal is to mitigate earthquake losses that can occur in many parts of the nation by providing earth science data and assessments essential for land-use planning, engineering design, and emergency preparedness decisions.
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Science and Products