David Lockner is a geophysicist in the Earthquake Science Center.
Science and Products
Whole-rock chemistry of core from serpentinite mud volcanoes, Northern Mariana subduction zone
We present whole-rock geochemical analyses of 12 core samples obtained from three serpentinite mud volcanoes (Yinazao, Asut Tesoru, and Fantangisna) located on the forearc of the Mariana subduction system, where the Pacific Plate descends beneath the Philippine Sea Plate. The core was collected during International Ocean Discovery Program Expedition 366 of 2016-2017. The materials comprising the m
Data from the manuscript: Direct evidence for fluid pressure, dilatancy, and compaction affecting slip in isolated faults
Earthquake instability occurs as a result of strength loss during sliding on a fault. It has been known for over 50 years that fault compaction or dilatancy may cause significant weakening or strengthening by dramatically changing the fluid pressure trapped in faults. Despite this fundamental importance, we have no real understanding of the exact conditions that lead to compaction or dilation duri
Data from the manuscript: Electrical properties and anisotropy of schists and fault rocks from New Zealand’s Southern Alps under confining pressure
Electrical resistivity measurements of Alpine Fault, NZ outcrop samples saturated with 0.1 M KCl brine and tested at confining pressure of 5 to 200 MP at room temperature.
Data release for effect of cationic species on the friction of clay-bearing faults
Data are time series of clay shearing tests presented in 'Friction in clay-bearing faults increases with the ionic radius of interlayer cations' by Sakuma et al. in Communications Earth & Environment, 2022. Data were used for Figure 1 and Supplementary Figure 8 in that paper. Files contain shear strength as a function of fault slip in laboratory tests for brine-saturated montmorillonite clay.
Geothermal slide-hold-slide experiments on bare surface Westerly granite
Laboratory slide-hold-slide tests, combined with flow through tests, conducted on Westerly granite with 30 degree sawcut. Tests were conducted with a constant confining pressure of 30 MPa with an average pore pressure of 10 MPa at temperatures of 23 and 200 degC. Three fluid flow conditions were examined (1) no flow, (2) cycled flow, and (3) continuous flow.
Data for "Weakening of Peridotite Sheared at Hydrothermal Conditions"
This data release comprises three separate datasets and their accompanying metadata, in zip files. The data were acquired as part of a laboratory study of the response of ultramafic materials to shear at hydrothermal conditions. The principal dataset consists of the strength-displacement data from 28 friction experiments acquired on gouges prepared from peridotite rock samples and from separates o
Data Release for the Susceptibility of Oklahoma's Basement to Seismic Reactivation Published in NGEO 2019
Recent widespread seismicity in Oklahoma is attributed to the reactivation of pre existing, critically-stressed, and seismically unstable faults due to decades of wastewater injection. However, the structure and properties of the reactivated faults remain concealed by the sedimentary cover. Here, we explore the major ingredients needed to induce earthquakes in Oklahoma by characterizing basement f
Data Release for Shear Failure of a Granite Pin Traversing a Sawcut Fault published in IJRMMS
Fault heterogeneities such as bumps, bends, and stepovers are commonly observed on natural faults but challenging to recreate under controlled laboratory conditions. We study deformation and microseismicity of a 76 mm-diameter Westerly granite cylinder with a sawcut fault with known frictional properties. An idealized asperity is added by emplacing a precision-ground 21 mm-diameter solid granite d
Data Release for Data Report: Permeability, porosity, and frictional strength of core samples from IODP Expedition 366 in the Mariana forearc
Core samples from the International Ocean Discovery Program (IODP) Expedition 366 were tested in the laboratory to determine permeability, porosity, density, and frictional strength and their relation to mineralogy as part of an effort to understand hydro-mechanical processes at convergent plate margins. Seven samples were tested from a depth range of 19.6 to 197.9 m below the sea floor. The sampl
Data for Frictional Properties and 3-D Stress Analysis of the Southern Alpine Fault, New Zealand (2013)
New Zealand's Alpine Fault (AF) ruptures quasi-periodically in large-magnitude earthquakes. Paleoseismological evidence suggests that about half of all recognized AF earthquakes terminated at the boundary between the Central and South Westland sections of the fault. There, fault geometry and the polarity of uplift change. The South Westland AF exhibits oblique-normal fault motion on a structure or
Data Release for "Role of Fault Gouge during Interaction between Hydraulic Fracture and a Preexisting Fracture"
Enhanced reservoir connectivity generally requires maximizing the intersection between hydraulic fracture (HF) and preexisting underground natural fractures (NF), while having the hydraulic fracture continue to propagate across the natural fractures. Observations of downhole core samples suggest that these natural fractures are in fact veins filled with minerals such as calcite (Mighani et al., 20
Glass deformation experiments under hydrothermal conditions
Six time-series data files are included in this release. The files contain mechanical data (described in metadata file below) collected during deformation experiments performed on obsidian gouge. A detailed description of the experiments along with the data reduction procedures are provided in the published manuscript titled Conversion of wet glass to melt at lower seismogenic zone conditions: i
Filter Total Items: 111
Strength recovery in quartzite is controlled by changes in friction in experiments at hydrothermal conditions up to 200°C
The rate of fault zone restrengthening between earthquakes can be influenced by both frictional and cohesive healing processes. Friction is dependent on effective normal stress while cohesion is independent of normal stress, potentially explaining—in part—the lack of depth dependence of earthquake stress drops. Although amenable to laboratory testing, few studies have systematically addressed the
Authors
Tamara Nicole Jeppson, David A. Lockner, Nicholas M. Beeler, Stephen H. Hickman
Effect of thermal and mechanical processes on hydraulic transmissivity evolution
Fracture healing is a critical component of enhanced geothermal systems, the earthquake cycle, and induced seismicity. Accordingly, there is significant interest in understanding the process of healing and its effects on fluid transport. The creation, reactivation, and sustainability of fracture networks depend on complex coupling among thermal, hydraulic, mechanical, and chemical processes. We us
Authors
Tamara Nicole Jeppson, David A. Lockner, Joshua M. Taron, Diane E. Moore, Brian D. Kilgore, Nicholas M. Beeler, Stephen H. Hickman
Friction in clay-bearing faults increases with the ionic radius of interlayer cations
Smectite can dramatically reduce the strength of crustal faults and may cause creep on natural faults without great earthquakes; however, the frictional mechanism remains unexplained. Here, our shear experiments reveal systematic increase in shear strength with the increase of the ionic radius of interlayer cations among lithium-, sodium-, potassium-, rubidium-, and cesium-montmorillonites, a smec
Authors
Hiroshi Sakuma, David A. Lockner, John Solum, Nick Davatzes
Electrical properties and anisotropy of schists and fault rocks from New Zealand’s Southern Alps under confining pressure
Magnetotelluric models spanning the Pacific–Australian Plate boundary in New Zealand’s South Island indicate a localized zone of low electrical resistivity that is spatially coincident with theductile mid-crustal part of the Alpine Fault Zone (AFZ). We explored the source of this anomaly bymeasuring the electrical properties of samples collected from surface outcrops approaching the AFZthat have a
Authors
Katherine E Kluge, Virginia G. Toy, David A. Lockner
Impact of fluid-rock interaction on strength and hydraulic transmissivity rvolution in shear fractures under hydrothermal conditions
Reactivated shear fractures contribute to the creation of pervasive fracture networks in geothermal systems. The creation, reactivation, and sustainability of fracture networks depend on complex coupling among thermal, hydraulic, mechanical, and chemical (THMC) processes. However, most laboratory experiments focus either solely on how fluid transport properties evolve in stationary fractures at el
Authors
Tamara Nicole Jeppson, David A. Lockner
Weakening of peridotite sheared at hydrothermal conditions
We conducted triaxial friction tests at hydrothermal conditions (25°C–350°C) on gouges of peridotite and its principal mineral constituents olivine and orthopyroxene. Pore-fluid chemistry was varied by the use of peridotite, granite, or quartzite driving blocks (representing wall rock) housing the gouge layer. Samples sheared at slow rates initially strengthen to a peak value, and then weaken towa
Authors
Diane E. Moore, David A. Lockner
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
Authors
Tamara Nicole Jeppson, David A. Lockner, Brian D. Kilgore, Nicholas M. Beeler, Joshua M. Taron
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
Authors
Tamara Nicole Jeppson, David A. Lockner, Brian D. Kilgore, Nicholas M. Beeler, Joshua M. Taron
A geology and geodesy based model of dynamic earthquake rupture on the Rodgers Creek‐Hayward‐Calaveras Fault System, California
The Hayward fault in California's San Francisco Bay area produces large earthquakes, with the last occurring in 1868. We examine how physics‐based dynamic rupture modeling can be used to numerically simulate large earthquakes on not only the Hayward fault, but also its connected companions to the north and south, the Rodgers Creek and Calaveras faults. Equipped with a wealth of images of this faul
Authors
Ruth A. Harris, Michael Barall, David A. Lockner, Diane E. Moore, David A. Ponce, Russell Graymer, Gareth J. Funning, Carolyn A. Morrow, Christodoulos Kyriakopoulos, Donna Eberhart-Phillips
Direct evidence for fluid pressure, dilatancy, and compaction affecting slip in isolated faults
Earthquake instability occurs as a result of strength loss during sliding on a fault. It has been known for over 50 years that fault compaction or dilatancy may cause significant weakening or strengthening by dramatically changing the fluid pressure trapped in faults. Despite this fundamental importance, we have no real understanding of the exact conditions that lead to compaction or dilation duri
Authors
Brooks P. Proctor, David A. Lockner, Brian D. Kilgore, Thomas M. Mitchell, Nicholas M. Beeler
The susceptibility of Oklahoma’s basement to seismic reactivation
Recent widespread seismicity in Oklahoma is attributed to the reactivation of pre-existing, critically stressed and seismically unstable faults due to decades of wastewater injection. However, the structure and properties of the reactivated faults remain concealed by the sedimentary cover. Here, we explore the major ingredients needed to induce earthquakes in Oklahoma by characterizing basement fa
Authors
Folarin Kolawole, C.S. Johnston, C.B. Morgan, Jefferson Chang, K Marfurt, David A. Lockner, Ze'ev Reches, B M Carpenter
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
Authors
Nicholas M. Beeler, David A. Lockner, Brian D. Kilgore, Greg McClaskey
Science and Products
- Data
Whole-rock chemistry of core from serpentinite mud volcanoes, Northern Mariana subduction zone
We present whole-rock geochemical analyses of 12 core samples obtained from three serpentinite mud volcanoes (Yinazao, Asut Tesoru, and Fantangisna) located on the forearc of the Mariana subduction system, where the Pacific Plate descends beneath the Philippine Sea Plate. The core was collected during International Ocean Discovery Program Expedition 366 of 2016-2017. The materials comprising the mData from the manuscript: Direct evidence for fluid pressure, dilatancy, and compaction affecting slip in isolated faults
Earthquake instability occurs as a result of strength loss during sliding on a fault. It has been known for over 50 years that fault compaction or dilatancy may cause significant weakening or strengthening by dramatically changing the fluid pressure trapped in faults. Despite this fundamental importance, we have no real understanding of the exact conditions that lead to compaction or dilation duriData from the manuscript: Electrical properties and anisotropy of schists and fault rocks from New Zealand’s Southern Alps under confining pressure
Electrical resistivity measurements of Alpine Fault, NZ outcrop samples saturated with 0.1 M KCl brine and tested at confining pressure of 5 to 200 MP at room temperature.Data release for effect of cationic species on the friction of clay-bearing faults
Data are time series of clay shearing tests presented in 'Friction in clay-bearing faults increases with the ionic radius of interlayer cations' by Sakuma et al. in Communications Earth & Environment, 2022. Data were used for Figure 1 and Supplementary Figure 8 in that paper. Files contain shear strength as a function of fault slip in laboratory tests for brine-saturated montmorillonite clay.Geothermal slide-hold-slide experiments on bare surface Westerly granite
Laboratory slide-hold-slide tests, combined with flow through tests, conducted on Westerly granite with 30 degree sawcut. Tests were conducted with a constant confining pressure of 30 MPa with an average pore pressure of 10 MPa at temperatures of 23 and 200 degC. Three fluid flow conditions were examined (1) no flow, (2) cycled flow, and (3) continuous flow.Data for "Weakening of Peridotite Sheared at Hydrothermal Conditions"
This data release comprises three separate datasets and their accompanying metadata, in zip files. The data were acquired as part of a laboratory study of the response of ultramafic materials to shear at hydrothermal conditions. The principal dataset consists of the strength-displacement data from 28 friction experiments acquired on gouges prepared from peridotite rock samples and from separates oData Release for the Susceptibility of Oklahoma's Basement to Seismic Reactivation Published in NGEO 2019
Recent widespread seismicity in Oklahoma is attributed to the reactivation of pre existing, critically-stressed, and seismically unstable faults due to decades of wastewater injection. However, the structure and properties of the reactivated faults remain concealed by the sedimentary cover. Here, we explore the major ingredients needed to induce earthquakes in Oklahoma by characterizing basement fData Release for Shear Failure of a Granite Pin Traversing a Sawcut Fault published in IJRMMS
Fault heterogeneities such as bumps, bends, and stepovers are commonly observed on natural faults but challenging to recreate under controlled laboratory conditions. We study deformation and microseismicity of a 76 mm-diameter Westerly granite cylinder with a sawcut fault with known frictional properties. An idealized asperity is added by emplacing a precision-ground 21 mm-diameter solid granite dData Release for Data Report: Permeability, porosity, and frictional strength of core samples from IODP Expedition 366 in the Mariana forearc
Core samples from the International Ocean Discovery Program (IODP) Expedition 366 were tested in the laboratory to determine permeability, porosity, density, and frictional strength and their relation to mineralogy as part of an effort to understand hydro-mechanical processes at convergent plate margins. Seven samples were tested from a depth range of 19.6 to 197.9 m below the sea floor. The samplData for Frictional Properties and 3-D Stress Analysis of the Southern Alpine Fault, New Zealand (2013)
New Zealand's Alpine Fault (AF) ruptures quasi-periodically in large-magnitude earthquakes. Paleoseismological evidence suggests that about half of all recognized AF earthquakes terminated at the boundary between the Central and South Westland sections of the fault. There, fault geometry and the polarity of uplift change. The South Westland AF exhibits oblique-normal fault motion on a structure orData Release for "Role of Fault Gouge during Interaction between Hydraulic Fracture and a Preexisting Fracture"
Enhanced reservoir connectivity generally requires maximizing the intersection between hydraulic fracture (HF) and preexisting underground natural fractures (NF), while having the hydraulic fracture continue to propagate across the natural fractures. Observations of downhole core samples suggest that these natural fractures are in fact veins filled with minerals such as calcite (Mighani et al., 20Glass deformation experiments under hydrothermal conditions
Six time-series data files are included in this release. The files contain mechanical data (described in metadata file below) collected during deformation experiments performed on obsidian gouge. A detailed description of the experiments along with the data reduction procedures are provided in the published manuscript titled Conversion of wet glass to melt at lower seismogenic zone conditions: i - Publications
Filter Total Items: 111
Strength recovery in quartzite is controlled by changes in friction in experiments at hydrothermal conditions up to 200°C
The rate of fault zone restrengthening between earthquakes can be influenced by both frictional and cohesive healing processes. Friction is dependent on effective normal stress while cohesion is independent of normal stress, potentially explaining—in part—the lack of depth dependence of earthquake stress drops. Although amenable to laboratory testing, few studies have systematically addressed theAuthorsTamara Nicole Jeppson, David A. Lockner, Nicholas M. Beeler, Stephen H. HickmanEffect of thermal and mechanical processes on hydraulic transmissivity evolution
Fracture healing is a critical component of enhanced geothermal systems, the earthquake cycle, and induced seismicity. Accordingly, there is significant interest in understanding the process of healing and its effects on fluid transport. The creation, reactivation, and sustainability of fracture networks depend on complex coupling among thermal, hydraulic, mechanical, and chemical processes. We usAuthorsTamara Nicole Jeppson, David A. Lockner, Joshua M. Taron, Diane E. Moore, Brian D. Kilgore, Nicholas M. Beeler, Stephen H. HickmanFriction in clay-bearing faults increases with the ionic radius of interlayer cations
Smectite can dramatically reduce the strength of crustal faults and may cause creep on natural faults without great earthquakes; however, the frictional mechanism remains unexplained. Here, our shear experiments reveal systematic increase in shear strength with the increase of the ionic radius of interlayer cations among lithium-, sodium-, potassium-, rubidium-, and cesium-montmorillonites, a smecAuthorsHiroshi Sakuma, David A. Lockner, John Solum, Nick DavatzesElectrical properties and anisotropy of schists and fault rocks from New Zealand’s Southern Alps under confining pressure
Magnetotelluric models spanning the Pacific–Australian Plate boundary in New Zealand’s South Island indicate a localized zone of low electrical resistivity that is spatially coincident with theductile mid-crustal part of the Alpine Fault Zone (AFZ). We explored the source of this anomaly bymeasuring the electrical properties of samples collected from surface outcrops approaching the AFZthat have aAuthorsKatherine E Kluge, Virginia G. Toy, David A. LocknerImpact of fluid-rock interaction on strength and hydraulic transmissivity rvolution in shear fractures under hydrothermal conditions
Reactivated shear fractures contribute to the creation of pervasive fracture networks in geothermal systems. The creation, reactivation, and sustainability of fracture networks depend on complex coupling among thermal, hydraulic, mechanical, and chemical (THMC) processes. However, most laboratory experiments focus either solely on how fluid transport properties evolve in stationary fractures at elAuthorsTamara Nicole Jeppson, David A. LocknerWeakening of peridotite sheared at hydrothermal conditions
We conducted triaxial friction tests at hydrothermal conditions (25°C–350°C) on gouges of peridotite and its principal mineral constituents olivine and orthopyroxene. Pore-fluid chemistry was varied by the use of peridotite, granite, or quartzite driving blocks (representing wall rock) housing the gouge layer. Samples sheared at slow rates initially strengthen to a peak value, and then weaken towaAuthorsDiane E. Moore, David A. LocknerStrength 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 granitAuthorsTamara Nicole Jeppson, David A. Lockner, Brian D. Kilgore, Nicholas M. Beeler, Joshua M. TaronEvolution 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 respAuthorsTamara Nicole Jeppson, David A. Lockner, Brian D. Kilgore, Nicholas M. Beeler, Joshua M. TaronA geology and geodesy based model of dynamic earthquake rupture on the Rodgers Creek‐Hayward‐Calaveras Fault System, California
The Hayward fault in California's San Francisco Bay area produces large earthquakes, with the last occurring in 1868. We examine how physics‐based dynamic rupture modeling can be used to numerically simulate large earthquakes on not only the Hayward fault, but also its connected companions to the north and south, the Rodgers Creek and Calaveras faults. Equipped with a wealth of images of this faulAuthorsRuth A. Harris, Michael Barall, David A. Lockner, Diane E. Moore, David A. Ponce, Russell Graymer, Gareth J. Funning, Carolyn A. Morrow, Christodoulos Kyriakopoulos, Donna Eberhart-PhillipsDirect evidence for fluid pressure, dilatancy, and compaction affecting slip in isolated faults
Earthquake instability occurs as a result of strength loss during sliding on a fault. It has been known for over 50 years that fault compaction or dilatancy may cause significant weakening or strengthening by dramatically changing the fluid pressure trapped in faults. Despite this fundamental importance, we have no real understanding of the exact conditions that lead to compaction or dilation duriAuthorsBrooks P. Proctor, David A. Lockner, Brian D. Kilgore, Thomas M. Mitchell, Nicholas M. BeelerThe susceptibility of Oklahoma’s basement to seismic reactivation
Recent widespread seismicity in Oklahoma is attributed to the reactivation of pre-existing, critically stressed and seismically unstable faults due to decades of wastewater injection. However, the structure and properties of the reactivated faults remain concealed by the sedimentary cover. Here, we explore the major ingredients needed to induce earthquakes in Oklahoma by characterizing basement faAuthorsFolarin Kolawole, C.S. Johnston, C.B. Morgan, Jefferson Chang, K Marfurt, David A. Lockner, Ze'ev Reches, B M CarpenterNear-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 natuAuthorsNicholas M. Beeler, David A. Lockner, Brian D. Kilgore, Greg McClaskey