David A Lockner
David Lockner is a geophysicist in the Earthquake Science Center.
Science and Products
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Constraints on the stress state of the San Andreas fault with analysis based on core and cuttings from SAFOD drilling phases 1 and 2 Constraints on the stress state of the San Andreas fault with analysis based on core and cuttings from SAFOD drilling phases 1 and 2
Analysis of field data has led different investigators to conclude that the San Andreas Fault (SAF) has either anomalously low frictional sliding strength (μ 0.2) or strength consistent with standard laboratory tests (μ > 0.6). Arguments for the apparent weakness of the SAF generally hinge on conceptual models involving intrinsically weak gouge or elevated pore pressure within the fault...
Authors
Cheryl Tembe, David A. Lockner, Teng-fong Wong
Geometry of the Nojima fault at Nojima-Hirabayashi, Japan - II. Microstructures and their implications for permeability and strength Geometry of the Nojima fault at Nojima-Hirabayashi, Japan - II. Microstructures and their implications for permeability and strength
Samples of damage-zone granodiorite and fault core from two drillholes into the active, strike-slip Nojima fault zone display microstructures and alteration features that explain their measured present-day strengths and permeabilities and provide insight on the evolution of these properties in the fault zone. The least deformed damage-zone rocks contain two sets of nearly perpendicular...
Authors
Diane E. Moore, D.A. Lockner, H. Ito, R. Ikeda, H. Tanaka, K. Omura
Geometry of the Nojima fault at Nojima-Hirabayashi, Japan - I. A simple damage structure inferred from borehole core permeability Geometry of the Nojima fault at Nojima-Hirabayashi, Japan - I. A simple damage structure inferred from borehole core permeability
The 1995 Kobe (Hyogo-ken Nanbu) earthquake, M = 7.2, ruptured the Nojima fault in southwest Japan. We have studied core samples taken from two scientific drillholes that crossed the fault zone SW of the epicentral region on Awaji Island. The shallower hole, drilled by the Geological Survey of Japan (GSJ), was started 75 m to the SE of the surface trace of the Nojima fault and crossed the...
Authors
David A. Lockner, Hidemi Tanaka, Hisao Ito, Ryuji Ikeda, Kentaro Omura, Hisanobu Naka
Premonitory acoustic emissions and stick-slip in natural and smooth-faulted Westerly granite Premonitory acoustic emissions and stick-slip in natural and smooth-faulted Westerly granite
A stick-slip event was induced in a cylindrical sample of Westerly granite containing a preexisting natural fault by loading at constant confining pressure of 150 MPa. Continuously recorded acoustic emission (AE) data and computer tomography (CT)-generated images of the fault plane were combined to provide a detailed examination of microscale processes operating on the fault. The dynamic...
Authors
B.D. Thompson, R.P. Young, David A. Lockner
Talc friction in the temperature range 25°–400 °C: relevance for fault-zone weakening Talc friction in the temperature range 25°–400 °C: relevance for fault-zone weakening
Talc is one of the weakest minerals that is associated with fault zones. Triaxial friction experiments conducted on water-saturated talc gouge at room temperature yield values of the coefficient of friction, μ(shear stress, τ/effective normal stress, σ′N) in the range 0.16–0.23, and μ increases with increasing σ′N. Talc gouge heated to temperatures of 100°–400 °C is consistently weaker...
Authors
Diane E. Moore, David A. Lockner
Comparative deformation behavior of minerals in serpentinized ultramafic rock: Application to the slab-mantle interface in subduction zones Comparative deformation behavior of minerals in serpentinized ultramafic rock: Application to the slab-mantle interface in subduction zones
The layer-structure minerals serpentine, brucite, and talc are postulated to form in the mantle wedge above a subducting slab as a result of progressive hydration and silica metasomatism. Tectonic mixing at the slab-mantle interface generates serpentinite mélanges that contain blocks of high-pressure (HP) or ultrahigh-pressure (UHP) metamorphic rock derived from the subducting slab. Such
Authors
Diane E. Moore, David A. Lockner
Science and Products
Filter Total Items: 14
No Result Found
Filter Total Items: 115
Constraints on the stress state of the San Andreas fault with analysis based on core and cuttings from SAFOD drilling phases 1 and 2 Constraints on the stress state of the San Andreas fault with analysis based on core and cuttings from SAFOD drilling phases 1 and 2
Analysis of field data has led different investigators to conclude that the San Andreas Fault (SAF) has either anomalously low frictional sliding strength (μ 0.2) or strength consistent with standard laboratory tests (μ > 0.6). Arguments for the apparent weakness of the SAF generally hinge on conceptual models involving intrinsically weak gouge or elevated pore pressure within the fault...
Authors
Cheryl Tembe, David A. Lockner, Teng-fong Wong
Geometry of the Nojima fault at Nojima-Hirabayashi, Japan - II. Microstructures and their implications for permeability and strength Geometry of the Nojima fault at Nojima-Hirabayashi, Japan - II. Microstructures and their implications for permeability and strength
Samples of damage-zone granodiorite and fault core from two drillholes into the active, strike-slip Nojima fault zone display microstructures and alteration features that explain their measured present-day strengths and permeabilities and provide insight on the evolution of these properties in the fault zone. The least deformed damage-zone rocks contain two sets of nearly perpendicular...
Authors
Diane E. Moore, D.A. Lockner, H. Ito, R. Ikeda, H. Tanaka, K. Omura
Geometry of the Nojima fault at Nojima-Hirabayashi, Japan - I. A simple damage structure inferred from borehole core permeability Geometry of the Nojima fault at Nojima-Hirabayashi, Japan - I. A simple damage structure inferred from borehole core permeability
The 1995 Kobe (Hyogo-ken Nanbu) earthquake, M = 7.2, ruptured the Nojima fault in southwest Japan. We have studied core samples taken from two scientific drillholes that crossed the fault zone SW of the epicentral region on Awaji Island. The shallower hole, drilled by the Geological Survey of Japan (GSJ), was started 75 m to the SE of the surface trace of the Nojima fault and crossed the...
Authors
David A. Lockner, Hidemi Tanaka, Hisao Ito, Ryuji Ikeda, Kentaro Omura, Hisanobu Naka
Premonitory acoustic emissions and stick-slip in natural and smooth-faulted Westerly granite Premonitory acoustic emissions and stick-slip in natural and smooth-faulted Westerly granite
A stick-slip event was induced in a cylindrical sample of Westerly granite containing a preexisting natural fault by loading at constant confining pressure of 150 MPa. Continuously recorded acoustic emission (AE) data and computer tomography (CT)-generated images of the fault plane were combined to provide a detailed examination of microscale processes operating on the fault. The dynamic...
Authors
B.D. Thompson, R.P. Young, David A. Lockner
Talc friction in the temperature range 25°–400 °C: relevance for fault-zone weakening Talc friction in the temperature range 25°–400 °C: relevance for fault-zone weakening
Talc is one of the weakest minerals that is associated with fault zones. Triaxial friction experiments conducted on water-saturated talc gouge at room temperature yield values of the coefficient of friction, μ(shear stress, τ/effective normal stress, σ′N) in the range 0.16–0.23, and μ increases with increasing σ′N. Talc gouge heated to temperatures of 100°–400 °C is consistently weaker...
Authors
Diane E. Moore, David A. Lockner
Comparative deformation behavior of minerals in serpentinized ultramafic rock: Application to the slab-mantle interface in subduction zones Comparative deformation behavior of minerals in serpentinized ultramafic rock: Application to the slab-mantle interface in subduction zones
The layer-structure minerals serpentine, brucite, and talc are postulated to form in the mantle wedge above a subducting slab as a result of progressive hydration and silica metasomatism. Tectonic mixing at the slab-mantle interface generates serpentinite mélanges that contain blocks of high-pressure (HP) or ultrahigh-pressure (UHP) metamorphic rock derived from the subducting slab. Such
Authors
Diane E. Moore, David A. Lockner