저작근 근전도에 관한 정상교합자와 ii급 부정교합자의 비교 연구

The study of preferred orientation of minerals in rocks dates back to Omalius d’Halloy (1833) who attributes a special significance to the alignment of crystals as an indicator of the formation process. Much later the influence of crystal alignment on physical properties was quantified (e.g., Weissenberg 1922, Voigt 1928, Reuss 1929). Only recently has this field emerged as a coherent part of earth science research linking such branches as mineralogy, petrology, structural geology, geodynamics and seismology. The reason for this was the emergence of quantitative methods to analyze preferred orientation, or “texture” as it was first called by Naumann (1850). These methods were largely developed in collaboration with materials science and mechanics. Quantitative measurements, detailed field studies, rigorous data analysis, theories to predict textures, and improvements in characterizing seismic anisotropy in the Earth are leading to a coherent picture that is now being refined.

Though seismologists have long accepted that there is a causal relationship between anisotropic propagation of seismic waves, the deformation field and crystal orientation, the prevailing view is still largely the mythological concept that seismic fast directions align with the flow direction. While this may be approximately the case for olivine deformed under certain conditions, it is certainly no universal law, as we will try to illustrate in this review. The “fast” direction of a crystal depends on the mineral species and its crystal structure. The alignment of crystals depends on microscopic, intra-crystalline deformation systems and the deformation history. Both relationships are complex and not intuitive, but there are well-established theories to compute single crystal physical properties as well as orientation patterns. Simulations can be compared with experimental data and then applied with some caution to the macroscopic Earth.

This review is intended to provide a brief introduction, highlighting some of the issues with …

Texture and Anisotropy

• Stability of steady frictional sliding, inertia and the quasi-static limit • work on ps 4; see course web site

The Mechanics Of Earthquakes And Faulting

A large number of polycrystalline materials, both manmade and natural, display preferred orientation of crystallites. Such alignment has a profound effect on anisotropy of physical properties. Preferred orientation or texture forms during growth or deformation and is modified during recrystallization or phase transformations and theories exist to predict its origin. Different methods are applied to characterize orientation patterns and determine the orientation distribution, most of them relying on diffraction. Conventionally x-ray polefigure goniometers are used. More recently single orientation measurements are performed with electron microscopes, both SEM and TEM. For special applications, particularly texture analysis at non-ambient conditions, neutron diffraction and synchrotron x-rays have distinct advantages. The review emphasizes such new possibilities. A second section surveys important texture types in a variety of materials with emphasis on technologically important systems and in rocks that contribute to anisotropy in the earth. In the former group are metals, structural ceramics and thin films. Seismic anisotropy is present in the crust (mainly due to phyllosilicate alignment), the upper mantle (olivine), the lower mantle (perovskite and magnesiowuestite) and the inner core (e-iron) and due to alignment by plastic deformation. There is new interest in the texturing of biological materials such as bones and shells. Preferred orientation is not restricted to inorganic substances but is also present in polymers that are not discussed in this review.

http://iopscience.iop.org/article/10.1088/0034-4885/67/8/R02/pdf

Texture and anisotropy

▶ Gathers original articles on topics in earth and planetary sciences ▶ Coverage includes geomagnetism, aeronomy, space science, seismology, volcanology, geodesy and planetary science ▶ Official journal of the Society of Geomagnetism and Earth, Planetary and Space Sciences, The Seismological Society of Japan, The Volcanological Society of Japan, The Geodetic Society of Japan, and The Japanese Society for Planetary Sciences

「Earth,Planets and Space」のオープンアクセス出版

Kinetics of pressure solution creep in quartz: theoretical considerations

Theories and applicability of grain size piezometers : The role of dynamic recrystallization mechanisms

A strength profile across the NE Japan interplate megathrust was constructed in the source region of the 2011 Tohoku-oki earthquake (Mw9.0) using friction, fracturing, and ductile flow data of the oceanic crustal materials obtained from laboratory experiments. The depth-dependent changes in pressure, temperature, and pore fluid pressure were incorporated into a model. The large tsunamigenic slips during the M9 event can be explained by a large gradient in fault strength on the up-dip side of the M9 hypocenter, which was located 17 to 18 km beneath sea level. A large stress drop (approximately 80 MPa) induced by the collapse of a subducted seamount possibly triggered the M9 earthquake. In the deep (>35 km) part of the thrust fault, where M7-class Miyagi-oki earthquakes have repeatedly occurred, plastic deformation occurs in siliceous rocks but not in gabbroic rocks. Thus, the asperity associated with the M7-class earthquakes was most likely a gabbroic body, such as a broken seamount, surrounded by siliceous sedimentary rocks. The conditionally stable nature of the surrounding region can be explained by the frictional behavior of wet quartz in the brittle-ductile transition zone. In contrast to the deep M7-class asperity, the M9 asperity (i.e., a region that was strongly coupled before the M9 Tohoku-oki earthquake) extended to a large area of the plate interface because shear strength is relatively insensitive to lithological variation at intermediate depths. However, the along-arc extension of the M9 asperity was constrained by fluid-rich regions on the plate interface.

/pdf/rheological-profile-across-the-ne-japan-interplate-3saxpamsya.pdf

Rheological profile across the NE Japan interplate megathrust in the source region of the 2011 Mw9.0 Tohoku-oki earthquake

The steady-state grain size of Earth materials undergoing solid state flow is estimated based on a nucleation-and-growth model of dynamic recrystallization. Assuming a nucleation mechanism of subgrain rotation, the mean diameter d of recrystallized grains is obtained as d/b = A(σ/µ)−p exp[-((Qgb - Qv)/mkT)], where b is the length of the Burgers vector, σ is differential stress, µ is the shear modulus, Qgb is the activation energy for the jump of an atom across the grain boundary, Qv is that for self-diffusion in the grain volume, k is the Boltzmann constant, T is temperature, A is a constant, p = 1.25 and m = 4 for intracrystalline nucleation, and p = 1.33 and m = 3 for grain-boundary nucleation. The exponent p = 1.25 ∼ 1.33 agrees well with available data for high- temperature dislocation creep of rock-forming minerals. A weak negative dependence of grain size on temperature is expected from this theory.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/1998GL900136

Stress and temperature dependence of recrystallized grain size: A subgrain misorientation model

[1] Shear-sliding tests were conducted on serpentine (antigorite) gouge to understand the rheology of serpentine-bearing faults The experiments were carried out using a constant confining pressure (100 MPa), a constant pore water pressure (30 MPa), and a range of temperatures (from room temperature to 600°C) The transient response in frictional behavior following stepwise changes in the slip velocity were documented at each temperature Slip rates varied between 00115 and 115 μm/s Both the general level of frictional strength and the transient responses changed drastically at around 450°C As the temperature increased from 400°C to 450°C, the strength of antigorite rose sharply The transient response also indicated a change in the mode of deformation from flow-type behavior at temperatures below 400°C to frictional behavior (stick-slip) at temperatures above 450°C–500°C Although only a limited volume of serpentine was involved in the dehydration reaction, X-ray diffraction analyses and scanning electron microscopy observations showed that forsterite had nucleated in the experimental products at the higher temperatures that were associated with frictional behavior Submicron-sized, streaky forsterite masses in shear-localized zones may be evidence of shear-induced dehydration that caused strengthening and embrittlement of the gouge Although antigorite rheology is complicated, the subsequent change in friction coefficient per order-of-magnitude change in sliding velocity increased with both increasing temperature and decreasing velocity, implying that a possible flow mechanism of intragranular deformation became activated

/pdf/on-the-transient-response-of-serpentine-antigorite-gouge-to-56vqzltjlv.pdf

Ichiko Shimizu

Papers

Kinetics of pressure solution creep in quartz: theoretical considerations

Theories and applicability of grain size piezometers : The role of dynamic recrystallization mechanisms

Rheological profile across the NE Japan interplate megathrust in the source region of the 2011 Mw9.0 Tohoku-oki earthquake

Stress and temperature dependence of recrystallized grain size: A subgrain misorientation model

On the transient response of serpentine (antigorite) gouge to stepwise changes in slip velocity under high-temperature conditions