Characterization of oriented cracks with differential strain analysis

Siegfried, Robert W.; Simmons, Gene

doi:10.1029/jb083ib03p01269

Cited by 64 publications

(21 citation statements)

References 17 publications

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“…In this test we used the tensor differential strain analysis (DSA) technique to provide a detailed description of the microcrack orientations and geometry[Simmons et al, 1974;Siegfried and Simmons, 1978;Plumb, 1979]. Strike and dip symbols with triangles refer to foliatio.'…”

mentioning

confidence: 99%

Near‐surface in situ stress: 2. A comparison with stress directions inferred from earthquakes, joints, and topography near Blue Mountain Lake, New York

Plumb¹,

Engelder²,

Sbar³

1984

J. Geophys. Res.

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At 11 outcrops within 100 km of Blue Mountain Lake, New York, we measured strain relaxation during overcoring of “surface,” “doorstopper,” and Bureau of Mines borehole deformation gauges. The majority of measurements showed a maximum expansion ε1 parallel with the contemporary tectonic stress field. To confirm further the orientation of in situ stress, at two sites, vertical fractures were induced at borehole walls using a packer‐fracturing technique. Several cores from each site were then tested for mechanical anisotropy using ultrasonic, compressibility, and thin section analyses. The orientations of mechanical anisotropy had a poor correlation with the preferred orientation of microcracks observed in thin section. The various techniques for measuring in situ stress orientations gave internally consistent results where ε1 generally aligned with topographic contours and often the mechanically stiff direction of the core. Furthermore, et aligned with the known contemporary tectonic stress, local p axes of earthquakes, Precambrian structures, and local joints. We interpret the alignment of ε1 and other structures to be the result of a feedback between the contemporary tectonic stress (ENE in the northeastern United States) and the process of jointing during the development of local topography. Hence ε1 is controlled by local structures and is a reflection of the contemporary tectonic stress but not a direct measure of it.

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confidence: 99%

Near‐surface in situ stress: 2. A comparison with stress directions inferred from earthquakes, joints, and topography near Blue Mountain Lake, New York

Plumb¹,

Engelder²,

Sbar³

1984

J. Geophys. Res.

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“…Orientation of the rift plane in the block was verified by viewing the microstructure of thin sections in an optical microscope [ Kudo et al , 1989]. The rift plane corresponds to a plane of variably developed biotite foliation that may lead to dilatancy anisotropy [ Scholz and Koczynski , 1979]; the biotite content of Westerly granite is about 5% [ Siegfried and Simmons , 1978]. The acoustic measurements were aimed at finding inherent defects in the sample associated with the rift plane.…”

Section: Measurements Of Elastic Tensor Of a Westerly Granite Samplementioning

confidence: 99%

Resonant acoustic spectroscopy of microfracture in a Westerly granite sample

et al. 2003

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[1] The experimental setup for precision acoustic measurements of the elastic tensor of structurally inhomogeneous materials has been designed and fabricated. The achieved accuracy of measurements is high enough for studying a fine structure of rocks. It is shown that resonant acoustic spectroscopy is a useful tool for measuring the small content of oriented microcracks that can be used for diagnostics of early stages of fracture when oriented microcracking occurs. Elastic characteristics of a Westerly granite sample have been investigated. The elastic tensor has been found to be hexagonal, oriented with respect to the rift plane. The obtained data have shown the presence of oriented microcracks and have been explained sensibly by a model of microcracks.

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“…Differential Strain AnalySiS (DSA) was used in, that study because it could determine, 1) the linear and volumetric compressibility as a function of pressure, 2) the strain associated with cracks of a particular closure pressure, and 3) the orientation of cracks with particular closure pressures. For details of sample preparation, data analysis and DSA theory, the reader 6 is referred to the original article (Strick:yand, et al , 1979), and to the works 8 0f Simmons et al , (1974) and Seigfried and Simmons (1978).…”

Section: Previous Researchmentioning

confidence: 99%