scholarly journals Lower crustal earthquake associated with highly pressurized frictional melts

2021 ◽  
Author(s):  
Xin Zhong ◽  
Arianne J. Petley-Ragan ◽  
Sarah H. M. Incel ◽  
Marcin Dabrowski ◽  
Niels H. Andersen ◽  
...  
Keyword(s):  
High Pressure ◽  
High Pressures ◽  
Maximum Principal Stress ◽  
Elastic Model ◽  
Differential Stress ◽  
Fault Surface ◽  
Seismic Fault ◽  
Crustal Earthquakes ◽  
Lower Crustal

AbstractEarthquakes at lower crustal depths are common during continental collision. However, the coseismic weakening mechanisms required to propagate an earthquake at high pressures are poorly understood. Transient high-pressure fluids or melts have been proposed as a viable mechanism, but verifying this requires direct in situ measurement of fluid or melt overpressure along fault planes that have hosted dynamic ruptures. Here, we report direct measurement of highly overpressurized frictional melts along a seismic fault surface. Using Raman spectroscopy, we identified high-pressure quartz inclusions sealed in dendritic garnets that grew from frictional melts formed by lower crustal earthquakes in the Bergen Arcs, Western Norway. Melt pressure was estimated to be 1.8–2.3 GPa on the basis of an elastic model for the quartz-in-garnet system. This is ~0.5 GPa higher than the pressure recorded by the surrounding pseudotachylyte matrix and wall rocks. The recorded melt pressure could not arise solely from the volume expansion of melting, and we propose that it was generated when melt pressure approached the maximum principal stress in a system subject to high differential stress. The associated palaeostress field demonstrates that a strong lower crust accommodated up to 1 GPa differential stress during the compressive stage of the Caledonian orogeny.

Lower crustal earthquake facilitated by overpressurized frictional melts

2020 ◽  
Author(s):  
Xin Zhong ◽  
Arianne Petley-Ragan ◽  
Sarah Incel ◽  
Marcin Dabrowski ◽  
Niels Andersen ◽  
...  
Keyword(s):  
Wall Rock ◽  
Rapid Quenching ◽  
Elastic Model ◽  
Shear Rigidity ◽  
Geological Time ◽  
Differential Stress ◽  
Crustal Earthquakes ◽  
Fluid Pressurization ◽  
Frictional Melting ◽  
Lower Crustal

<p>Earthquakes are among the most catastrophic geological events that last only several to tens of seconds. During earthquakes, many processes may occur including rupturing, frictional sliding, pore fluid pressurization and occasionally frictional melting. However, little direct records of these fast processes remain preserved through geological time. During rapid shearing, frictional melt may form that lubricates the rocks and facilitates further sliding. The frictional melt layer may quench quickly within seconds to minutes depending on its thickness. After quenching, the product pseudotachylyte preserves valuable information about the conditions when the frictional melt was generated. Here, we study pseudotachylyte from Holsnøy Island in the Bergen Arcs of Western Norway, an exhumed portion of the lower continental crust. The investigated pseudotachylyte vein is ca. 1-2 cm thick and free of injection veins along the 2 m visible length of the fault. The pseudotachylyte matrix is made up of fine-grained omphacite (Jd<sub>38</sub>), sodic plagioclase (Ab<sub>83</sub>) and kyanite with minor rutile and sulphides. Many dendritic garnets are found within the pseudotachylyte showing gradual grain size reduction towards the wall rock. This suggests that the garnets crystallized during rapid quenching. The stability of epidote, kyanite and quartz in the wall rock plagioclase, and omphacite and albitic plagioclase together with quartz in the pseudotachylyte matrix constrains the ambient P ca. 1.5-1.7 GPa and T ca. 650-750°C. Using Raman elastic barometry, the constrained pressure condition from quartz inclusions in the dendritic garnets in the pseudotachylyte is > 2 GPa. Based on an elastic model (Eshelby’s solution), it is not possible to maintain 0.5 GPa overpressure within a thin melt layer by thermal pressurization or melting expansion. A potential explanation is that GPa level differential stress was present in the wall rocks and the melt pressure approached the normal stress when shear rigidity vanished during frictional melting. Our study illustrates how overpressure can be created within frictional melt veins under conditions of high differential stress, and offers a mechanism that facilitates co-seismic weakening during lower crustal earthquakes.  </p>

High-Pressure Phase Transitions of Cubic Y 2 O 3 under High Pressures by In-situ Synchrotron X-Ray Diffraction

2019 ◽  
Vol 36 (4) ◽  
pp. 046103 ◽  
Author(s):  
Sheng Jiang ◽  
Jing Liu ◽  
Xiao-Dong Li ◽  
Yan-Chun Li ◽  
Shang-Ming He ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
High Pressures ◽  
High Pressure Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pressure Phase

scholarly journals The solvothermal synthesis of γ-AlOOH nanoflakes and their compression behaviors under high pressures

RSC Advances ◽  
2017 ◽  
Vol 7 (9) ◽  
pp. 4904-4911 ◽  
Author(s):  
Xudong Zhou ◽  
Jian Zhang ◽  
Yanmei Ma ◽  
Hui Tian ◽  
Yue Wang ◽  
...  
Keyword(s):  
High Pressure ◽  
Synchrotron Radiation ◽  
Solvothermal Synthesis ◽  
High Pressures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Radiation Angle

The compression behaviors of γ-AlOOH nanoflakes were investigated via in situ high pressure synchrotron radiation angle dispersive X-ray diffraction techniques.

p-Aminobenzoic acid polymorphs under high pressures

RSC Advances ◽  
2014 ◽  
Vol 4 (30) ◽  
pp. 15534-15541 ◽  
Author(s):  
Tingting Yan ◽  
Kai Wang ◽  
Defang Duan ◽  
Xiao Tan ◽  
Bingbing Liu ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Pressure ◽  
Diamond Anvil Cell ◽  
High Pressures ◽  
Aminobenzoic Acid ◽  
Aminobenzoic Acids ◽  
Diamond Anvil

The effect of high pressure on two forms (α, β) of p-aminobenzoic acids (PABA) is studied in a diamond anvil cell using in situ Raman spectroscopy.

X-ray diffraction study of HgBa2CuO4+δ at high pressures

1997 ◽  
Vol 12 (2) ◽  
pp. 106-112
Author(s):  
Eduardo J. Gonzalez ◽  
Winnie Wong-Ng ◽  
Gasper J. Piermarini ◽  
Christian Wolters ◽  
Justin Schwartz
Keyword(s):  
High Pressure ◽  
Bulk Modulus ◽  
Pressure Range ◽  
High Pressures ◽  
Anisotropy Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Anisotropic Elastic ◽  
High Pressure Study

An in situ high pressure study using energy dispersive X-ray diffraction has been carried out on the polycrystalline high-Tc superconductor, HgBa2CuO4+δ (Hg-1201), to study its phase stability under pressure and also to measure its compressibility and bulk modulus. No evidence of pressure-induced polymorphism was found in the pressure range investigated, i.e., from 0.1 MPa (1 atm) to 5 GPa. The compound exhibited anisotropic elastic properties. The axial compressibility along the c axis was measured to be (3.96±0.35)×10−3GPa−1 and along the a axis (3.42±0.13)×10−3GPa−1, corresponding to an anisotropy ratio of 1.16±0.11. The bulk modulus was determined to be (94.7±4.2) GPa and, assuming a Poisson's ratio of 0.2, Young's modulus was estimated to be (170±8) GPa.

In situquantitative analysis of stress and texture development in forsterite aggregates deformed at 6 GPa and 1373 K

2012 ◽  
Vol 45 (2) ◽  
pp. 263-271 ◽  
Author(s):  
Caroline Bollinger ◽  
Sébastien Merkel ◽  
Paul Raterron
Keyword(s):  
High Pressure ◽  
National Laboratory ◽  
Brookhaven National Laboratory ◽  
Texture Development ◽  
Elastic Response ◽  
Differential Stress ◽  
Plastic Properties ◽  
X Ray ◽  
Strain And Strain Rate

The investigation of materials plastic properties at high pressure is a fast-growing field, owing to the coupling of high-pressure deformation apparatuses with X-ray synchrotron radiation. In such devices, materials strain and strain rate are measured by time-resolved radiography, while differential stress is deduced from the elastic response of thedspacing of the crystallographic planes as measured by X-ray diffraction. Here a new protocol is presented, which allows thein situmeasurement of stress and texture development in aggregates deformed at high pressure for experiments carried out with the recently installed ten-element energy-dispersive detector at the X17B2 beamline of the National Synchrotron Light Source (Brookhaven National Laboratory, Upton, NY, USA). Cycling deformation of a forsterite specimen was carried out at a pressure of ∼6 GPa and a temperature of ∼1373 K, using a deformation-DIA apparatus. Diffraction peak energies are analysed in terms of differential stress and principal stress direction, while the intensities of peaks obtained at different azimuths are analysed in terms of lattice preferred orientation (LPO). The development and evolution of a marked LPO, with the (010) plane perpendicular to the compression axis, is observedin situduring the run and is confirmed by electron backscatter diffraction measurements on the run product.

scholarly journals Impedance spectroscopy for in situ and real-time observations of the effects of hydrogen on nitrile butadiene rubber polymer under high pressure

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jae Kap Jung ◽  
Sang Koo Jeon ◽  
Kyu-Tae Kim ◽  
Chang Hoon Lee ◽  
Un Bong Baek ◽  
...  
Keyword(s):  
High Pressure ◽  
Impedance Spectroscopy ◽  
Real Time ◽  
High Pressures ◽  
Hydrogen Gas ◽  
Physicochemical Interaction ◽  
Butadiene Rubber ◽  
Current Conservation ◽  
Nitrile Butadiene Rubber

Abstract Nondestructive impedance spectroscopy (IS) was developed and demonstrated to detect the effects of hydrogen on nitrile butadiene rubber exposed to hydrogen gas (H2) at high pressures up to 10 MPa. IS was applied to obtain an in situ and real-time quantification of H2 penetration into and its desorption out of rubber under high pressure. The diffusion coefficients of H2 were also obtained from the time evolution of the capacitance, which were compared with those obtained by thermal desorption gas analysis. The in situ measurements of the capacitance and the dissipation factor under various pressures during cyclic stepwise pressurization and decompression demonstrated the diffusion behaviour of H2, the phase of the rubber under high pressure, the transport properties of H2 gas, and the physicochemical interaction between H2 and the rubber. These phenomena were supported by a COMSOL simulation based on the electric current conservation equation and scanning electron microscopy (SEM) observations.

Single Crystal Growth of High-Pressure Phases of Ice and Salt Hydrate Far Below the Original Melting Point by Mixing Alcohol: Crystal Structure Determination of Magnesium Chloride Heptahydrate

2020 ◽  
Author(s):  
Keishiro Yamashita ◽  
Kazuki Komatsu ◽  
Hiroyuki Kagi
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Crystal Growth ◽  
Single Crystal ◽  
Room Temperature ◽  
Growth Technique ◽  
Salt Hydrate ◽  
X Ray

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.50 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.

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