Fossil intermediate-depth earthquakes in subducting slabs linked to differential stress release

Intermediate-depth subduction seismicity is still hiding most of its secrets. While plate unbending is recognised as the main stress loading mechanism, the processes responsible for earthquake nucleation are still unclear and depend upon the question whether failure occur in a wet dehydrating slab or in a completely dry lithosphere.&#160;The recent observation of subduction-related pseudotachylytes (quenched frictional melts produced during seismic slip along a fault) in the dry ophiolites of Moncuni (Lanzo Massif, W. Alps)1, an exhumed example of the actual intermediate-depth seismicity, and the interpretation of seismic data from various double-plane seismic zones in subducting slabs2&#160;suggest that the seismogenic portions of subducting oceanic slabs can be dominantly dry. In absence of a fluid-mediated embrittlement (i.e. dehydration embrittlement), a dry and strong slab requires extremely high differential stress for brittle failure to occur.Here we investigate with numerical simulations the potential of a subducting dry oceanic slab of building up the high differential stress required for failure. We performed pseudo-2D thermo-mechanical simulations of free subduction of a dry slab in the asthenosphere considering a visco-elasto-plastic rheology. We tested both a homogeneous dry plate and a dry plate with scattered weak circular inclusions representing domains of partial hydration in the first 40 km of the slab.The stress field in the unbending portion of the slab describes two arcs, the outer one in compression and the inner one in extension, in agreement with the two planes of seismicity. For the homogenous plate the maximum values of differential stress are around 1 GPa, i.e. not high enough for triggering earthquakes.&#160;The presence of weak inclusions induces a stress amplification, which can be of several folds if elastic properties of the inclusions are sufficiently degraded, but still maintaining a high viscosity. For inclusions with a shear modulus decreased by 60-70% relative to the surrounding material, but similar viscosity, stress values in excess of 4 GPa are obtained, high enough for brittle failure at 100 km of depth. This inclusion rheology is compatible with that of a slightly hydrated and serpentinized meta-peridotite. These meta-peridotite domains are likely to be found in the oceanic lithosphere around faults related to slab bending which represent the main pathways for fluid infiltration in the slab.We conclude that extremely high deviatoric stresses can be achieved in dry and strong subducting plates in presence of scattered domains of meta-peridotite acting as local stress amplifiers. These previously unreported stress values may explain brittle seismic failure at intermediate depth conditions.&#160;References:1: Pennacchioni et al., 2020, Record of intermediate-depth subduction seismicity in a dry slab from an exhumed ophiolite, Earth Planet. Sc. Lett. 548, 1164902: Florez and Prieto, 2019, Controlling factors of seismicity and geometry in double seismic zones, Geophys. Res. Lett. 46, 4171-4181

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Faculty Opinions recommendation of Starvation-dependent differential stress resistance protects normal but not cancer cells against high-dose chemotherapy.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1104940.571381 ◽

2008 ◽

Author(s):

Audrey Gasch

Keyword(s):

Cancer Cells ◽

Stress Resistance ◽

High Dose Chemotherapy ◽

High Dose ◽

Differential Stress ◽

Differential Stress Resistance

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The cycle of instability: stress release and fissure flow as controls on gully head retreat

Hydrological Processes ◽

10.1002/hyp.150 ◽

2001 ◽

Vol 15 (1) ◽

pp. 3-12 ◽

Cited By ~ 31

Author(s):

A. J. C. Collison

Keyword(s):

Stress Release ◽

Gully Head

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Consideration on modeling of Nb sorption onto clay minerals

Radiochimica Acta ◽

10.1515/ract-2020-0006 ◽

2020 ◽

Vol 108 (11) ◽

pp. 873-877

Author(s):

Tetsuji Yamaguchi ◽

Saki Ohira ◽

Ko Hemmi ◽

Logan Barr ◽

Asako Shimada ◽

...

Keyword(s):

Distribution Coefficient ◽

Clay Minerals ◽

Safety Assessment ◽

Distribution Coefficients ◽

Surface Species ◽

Complex Species ◽

Intermediate Depth ◽

Speciation Model ◽

Surface Phases ◽

High Distribution Coefficient

AbstractSorption distribution coefficient (Kd) of niobium-94 on minerals are an important parameter in safety assessment of intermediate-depth disposal of waste from core internals etc. The Kd of Nb on clay minerals in Ca(ClO4)2 solutions were, however, not successfully modeled in a previous study. The high distribution coefficients of Nb on illite in Ca(ClO4)2 solutions were successfully reproduced by taking Ca–Nb–OH surface species into account. Solubility of Nb was studied in Ca(ClO4)2 solutions and the results were reproduced by taking an aqueous Ca–Nb–OH complex species, CaNb(OH)6+, into account in addition to previously reported Nb(OH)6− and Nb(OH)72−. Based on this aqueous speciation model, the Ca–Nb–OH surface species responsible for the sorption of Nb on illite in Ca(ClO4)2 solutions was presumed to be X_OCaNb(OH)6. Although uncertainties exist in the speciation of aqueous Ca–Nb–OH species, the result of this study proposed a possible mechanism for high distribution coefficient of Nb on illite in Ca(ClO4)2 solutions. The mechanism includes Ca–Nb–OH complex formation in aqueous, solid and surface phases.

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Residual Stress Release and Its Effects on the Fatigue Strength of Typical Welded Joints in Cone-Cylinder Pressure Structures

Applied Ocean Research ◽

10.1016/j.apor.2021.102673 ◽

2021 ◽

Vol 111 ◽

pp. 102673

Author(s):

Liangbi Li ◽

Jingxi Zhang ◽

Yiwen Zhang ◽

Deqin Zhu ◽

Zhengquan Wan ◽

...

Keyword(s):

Residual Stress ◽

Fatigue Strength ◽

Welded Joints ◽

Cylinder Pressure ◽

Stress Release

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Comment and Reply on “Differential stress magnitudes during regional deformation and metamorphism: Upper bound imposed by tensile fracturing”

Geology ◽

10.1130/0091-7613(1984)12<56b:carods>2.0.co;2 ◽

1984 ◽

Vol 12 (1) ◽

pp. 56 ◽

Cited By ~ 1

Author(s):

Michael A. Etheridge

Keyword(s):

Upper Bound ◽

Differential Stress ◽

Regional Deformation ◽

Tensile Fracturing

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Elevation of gene expression of Btg2, Gadd 153, and antioxidant markers in RONS-induced PC12 cells

Beni-Suef University Journal of Basic and Applied Sciences ◽

10.1186/s43088-020-00080-w ◽

2020 ◽

Vol 9 (1) ◽

Author(s):

Aravind P ◽

Sarojini R. Bulbule ◽

Hemalatha N ◽

Anushree G ◽

Babu R.L ◽

...

Keyword(s):

Gene Expression ◽

Endoplasmic Reticulum ◽

Protein Expression ◽

Pc12 Cells ◽

Expression Pattern ◽

High Glucose ◽

Nitrosative Stress ◽

Gene Expression Pattern ◽

Marker Genes ◽

Differential Stress

Abstract Background Free radicals generated in the biological system bring about modifications in biological molecules causing damage to their structure and function. Identifying the damage caused by ROS and RNS is important to predict the pathway of apoptosis due to stress in PC12 cells. The first defense mechanisms against them are antioxidants which act in various pathways through important cellular organelles like the mitochondria and endoplasmic reticulum. Specific biomarkers like Gadd153 which is a marker for endoplasmic reticulum stress, Nrf2 which responds to the redox changes and translocates the antioxidant response elements, and Btg2 which is an antioxidant regulator have not been addressed in different stress conditions previously in PC12 cells. Therefore, the study was conducted to analyze the gene expression pattern (SOD, Catalase, Btg2, Gadd153, and Nrf2) and the protein expression pattern (iNOS and MnSOD) of the antioxidant stress markers in differential stress-induced PC12 cells. Peroxynitrite (1 μM), rotenone (1 μM), H2O2(100 mM), and high glucose (33 mM) were used to induce oxidative and nitrosative stress in PC12 cells. Results The results obtained suggested that rotenone-induced PC12 cells showed a significant increase in the expression of catalase, Btg2, and Gadd153 compared to the control. Peroxynitrite-induced PC12 cells showed higher expression of Btg2 compared to the control. H2O2 and high glucose showed lesser expression compared to the control in all stress marker genes. In contrast, the Nrf2 gene expression is downregulated in all the stress-induced PC12 cells compared to the control. Further, MnSOD and iNOS protein expression studies suggest that PC12 cells exhibit a selective downregulation. Lower protein expression of MnSOD and iNOS may be resulted due to the mitochondrial dysfunction in peroxynitrite-, high glucose-, and H2O2-treated cells, whereas rotenone-induced cells showed lower expression, which could be the result of a dysfunction of the endoplasmic reticulum. Conclusion Different stress inducers like rotenone, peroxynitrite, H2O2, and high glucose increase the NO and ROS. Btg2 and Gadd153 genes were upregulated in the stress-induced cells, whereas the Nrf2 was significantly downregulated in differential stress-induced PC12 cells. Further, antioxidant marker genes were differentially expressed with different stress inducers.

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