Residual stress preserved in quartz from the San Andreas Fault Observatory at Depth

Chen, Kai; Kunz, Martin; Tamura, Nobumichi; Wenk, Hans‐Rudolf

doi:10.1130/g36443.1

Cited by 41 publications

(37 citation statements)

References 26 publications

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“…This could be interpreted as partially released elastic strain close to the free surface of the sample as suggested by Chen et al (2015), who obtain the same results for a deformed quartz grain in the San Andreas fault zone. However, as the studied NOJ220 thin section is horizontal, such lower ε ZZ component strain component could be also related to the strike-slip tectonic environment of the Nojima fault during the Paleocene (Famin et al, 2014) corresponding to a vertical minimum compressive stress at that 20 geological time.…”

Section: Elastic Strain and Residual Stresssupporting

confidence: 71%

“…For example, differential stress measured in the SAFOD pilot hole are ≈60 MPa at 1671m depth (Hickman and Zoback, 2004). This value is considerably lower than 15 the up to 300 MPa residual stress measured by Chen et al (2015) in quartz fragments within the damage zone of the San Andreas fault at 2.7 km depth (ca 100 MPa confining pressure) using X-ray Laue microdiffraction. This is the unique residual stress value available in a damaged fault zone.…”

Section: Introductionmentioning

confidence: 57%

“…We will compare the deformation microstructures of that sample 10 with experimentally produced microstructures during dynamic loading and with naturally fragmented fault rocks described in the literature. For microstructural observations, techniques of petrographic microscopy, Scanning Electron Microscopy (SEM), cathodoluminescence (CL), Electron Back Skattered Diffraction (EBSD) and X-ray Laue microdiffraction were used to characterize microfractures, their cement and the intragranular heterogeneities of crystallographic orientation in quartz grains, and to map the elastic strains and residual stresses as Chen et al (2015) have done for a sample of the San 15 Andreas fault zone. We will discuss the significance of the results in terms of stress and strain-rate and the contribution of the observed microscopic damage to the widening of the damaged fault zone.…”

Section: Introductionmentioning

confidence: 99%

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High stresses stored in fault zones: example of the Nojima fault (Japan)

Boullier¹,

Robach²,

Ildefonse³

et al. 2017

Preprint

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Abstract. During the last decade pulverized rocks have been described on outcrops along large active faults and attributed to damage related to a propagating seismic rupture front. Questions remain on the maximal lateral distance from the fault plane and maximal depth for dynamic damage to be imprinted in rocks. In order to document these questions, a core sample of granodiorite located at 51.3 m from the Nojima fault (Japan) that was drilled after the Hyogo-ken Nanbu (Kobe) earthquake is studied by using Electron Back-Scattered Diffraction (EBSD) and high resolution X-ray Laue 15 microdiffraction. Although located outside of the Nojima damage fault zone and macroscopically undeformed, the sample shows pervasive microfractures and local fragmentation that are attributed to the first stage of seismic activity along the Nojima fault characterized by laumontite as the main sealing mineral. EBSD mapping was used in order to characterize the crystallographic orientation and deformation microstructures in the sample, and X-ray microdiffraction to measure elastic strain and residual stresses in a quartz grain. Both methods give consistent results on the crystallographic orientation and 20show small and short wave-length misorientations associated with laumontite-sealed microfractures and alignments of tiny fluid inclusions. Deformation microstructures in quartz are symptomatic of the semi-brittle faulting regime, in which low temperature brittle, plastic deformation and stress-driven dissolution-deposition processes occur conjointly.Residual stresses are calculated from elastic strain measured by X-ray Laue microdiffraction and stress peaks at 100 MPa (mean 141 MPa). Such stress values are comparable to the peak strength of a damaged granodiorite from the damage zone 25 of the Nojima fault indicating that, although apparently macroscopically undeformed, the sample is actually highly damaged. The homogeneously distributed microfracturing of quartz is the microscopically visible imprint of this damage and suggests that high stresses were stored in the whole sample and not only concentrated on some crystal defects. It is proposed that the high residual stresses are the sum of the stress fields associated with individual dislocations, dislocation microstructures and originated from the dynamic damage related to the propagation of rupture fronts or seismic waves 30 associated to M6 to M7 earthquakes during Paleocene on the Nojima fault at a 3.7 -11.1 km depth (laumontite stability domain) where confining pressure prevented pulverization. The high residual stresses and the deformation microstructures Solid Earth Discuss., https://doi

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Section: Elastic Strain and Residual Stresssupporting

confidence: 71%

Section: Introductionmentioning

confidence: 57%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

High stresses stored in fault zones: example of the Nojima fault (Japan)

Boullier¹,

Robach²,

Ildefonse³

et al. 2017

Preprint

View full text Add to dashboard Cite

show abstract

“…This technique provides high resolution of both crystal orientation (0.01 o ) [58] and of deviatoric strain (~10 -4 ) [59], while the defect type and density distribution in the scan area can also be revealed from the shape of the diffraction peaks [60][61].…”

Section: Methodsmentioning

confidence: 99%

A study of deformation and strain induced in bulk by the oxide layers formation on a Fe-Cr-Al alloy in high-temperature liquid Pb-Bi eutectic

et al. 2018

Self Cite

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At elevated temperatures, heavy liquid metals and their alloys are known to create a highly corrosive environment that causes irreversible degradation of most iron-based materials. It has been found that an appropriate concentration of oxygen in the liquid alloy can significantly reduce this issue by creating a passivating oxide scale that controls diffusion, especially if Al is present in Fe-based materials (by Al-oxide formation). However, the increase of the temperature and of oxygen content in liquid phase leads to the increase of oxygen diffusion into bulk, and to promotion of the internal Al oxidation. This can cause a strain in bulk near the oxide layer, due either to mismatch between the thermal expansion coefficients of the oxides and bulk material, or to misfit of the crystal lattices (bulk vs. oxides). This work investigates the strain induced into proximal bulk of a Fe-Cr-Al alloy by oxide layers formation in liquid lead-bismuth eutectic utilizing synchrotron X-ray Laue microdiffraction. It is found that internal oxidation is the most likely cause for the strain in the metal rather than thermal expansion mismatch as a two-layer problem.Dear Sir, I re-submit our paper entitled: "A study of deformation and strain induced in bulk by the oxide layers formation on a Fe-Cr-Al alloy in high-temperature liquid Pb-Bi eutectic" on behalf of all co-authors to Acta Materialia, after addressing all the revisions stated by the reviewer. In the study, we analyze a strain in the near-interface bulk of ferritic FeCrAl alloy after its exposure to heavy liquid metals. Two possible origins of strain were considered: internal oxidation of aluminum in bulk, and thermal expansion mismatch between the oxide and the bulk. A positive correlation of dislocation density with peak width distribution indicates that strain comes from plastic deformation, while the evidence of grain refinement and sub-grain formation indicates a noticeable internal oxidation. Based on the comparison with theoretical predictions, we conclude that internal oxidation is more dominant mechanism of strain induction.Sincerely, Miroslav P. Popovic, UC Berkeley Cover LetterWe thank the reviewer for his/her time and effort.Below we address all reviewer's comments (labeled "C") in detail, marked in green (labeled "A").C 0: -Dear authors, congratulations for this interesting work.A 0: We thank the reviewer for his/her assessment of our paper. C1-1: You are studying the deformation and strain induced in the bulk of a Fe-Cr-Al alloy (Alkrothal 720) by oxide scales that form in liquid LBE. Alkrothal is a bcc alloy, a fact that you should clearly mention when you describe the material in the Experimental section (not just mention that it is a ferritic alloy), giving some basic information on the lattice parameters. A1-2: We thank the reviewer for this suggestion. We made changes in the manuscript and modified our statement (in the first paragraph of section 2. Experimental), so it reads now as following: C1-2. What you neglect to mention, however, is th...

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“…40 More generally, both white and monochromatic micro-and nanobeam diffraction methods have evolved in various fi elds of research. Besides the trend of extensive applications in geophysics, 41 mineralogy, and biomineralogy, 42 , 43 the intensive combination with electron microscopy to explore the nanoscale world 44 , 45 has matured, in conjunction with ongoing improvements in the dataanalysis approaches. 46 , 47 The article by X. Chen et al emphasizes some new features and further developments of these techniques, including the signifi cant improvement of spatial resolution at the Taiwan Photon Source, and small-molecule structure refi nement by interpreting the monochromatic and polychromatic x-ray diffraction signals from the same crystal.…”

Section: Imaging and Spatial Mappingmentioning

confidence: 99%