Possible depth and source localization of seismic anisotropy beneath Shillong Plateau and Himalayan foredeep region: An implication towards deformation mechanisms

2021 ◽  
Author(s):  
Debasis D. Mohanty ◽  
Satyapriya Biswal ◽  
Manoj Kumar Phukan ◽  
Eluyemi A. Ayodeji
Keyword(s):  
Source Localization ◽  
Seismic Anisotropy ◽  
Deformation Mechanisms ◽  
Shillong Plateau

scholarly journals Competing Deformation Mechanisms in Periclase: Implications for Lower Mantle Anisotropy

Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 650 ◽  
Author(s):  
Feng Lin ◽  
Samantha Couper ◽  
Mike Jugle ◽  
Lowell Miyagi
Keyword(s):  
Lower Mantle ◽  
Seismic Anisotropy ◽  
Shear Velocity ◽  
Deformation Mechanisms ◽  
Effect Of Temperature ◽  
Lattice Strains ◽  
Slip Activity ◽  
Consistent Method ◽  
Mantle Anisotropy ◽  
Low Shear

Seismic anisotropy is observed above the core-mantle boundary in regions of slab subduction and near the margins of Large Low Shear Velocity Provinces (LLSVPs). Ferropericlase is believed to be the second most abundant phase in the lower mantle. As it is rheologically weak, it may be a dominant source for anisotropy in the lowermost mantle. Understanding deformation mechanisms in ferropericlase over a range of pressure and temperature conditions is crucial to interpret seismic anisotropy. The effect of temperature on deformation mechanisms of ferropericlase has been established, but the effects of pressure are still controversial. With the aim to clarify and quantify the effect of pressure on deformation mechanisms, we perform room temperature compression experiments on polycrystalline periclase to 50 GPa. Lattice strains and texture development are modeled using the Elasto-ViscoPlastic Self Consistent method (EVPSC). Based on modeling results, we find that { 110 } ⟨ 1 1 ¯ 0 ⟩ slip is increasingly activated with higher pressure and is fully activated at ~50 GPa. Pressure and temperature have a competing effect on activities of dominant slip systems. An increasing { 100 } ⟨ 011 ⟩ : { 110 } ⟨ 1 1 ¯ 0 ⟩ ratio of slip activity is expected as material moves from cold subduction regions towards hot upwelling region adjacent to LLSVPs. This could explain observed seismic anisotropy in the circum-Pacific region that appears to weaken near margins of LLVSPs.

Crustal seismic anisotropy beneath Shillong plateau - Assam valley in North East India: Shear-wave splitting analysis using local earthquakes

2017 ◽  
Vol 717 ◽  
pp. 425-432 ◽  
Author(s):  
Antara Sharma ◽  
Santanu Baruah ◽  
Davide Piccinini ◽  
Sowrav Saikia ◽  
Manoj K. Phukan ◽  
...  
Keyword(s):  
Shear Wave ◽  
Seismic Anisotropy ◽  
Shear Wave Splitting ◽  
Shillong Plateau ◽  
North East India ◽  
Local Earthquakes ◽  
North East ◽  
Wave Splitting

Deformation mechanisms and seismic anisotropy in lower crustal rocks from the Barro Alto Complex, Central Brazil

2021 ◽  
pp. 229087
Author(s):  
CamilaSantos Silveira ◽  
Leonardo Lagoeiro ◽  
Carolina Cavalcante ◽  
Rhander Taufner ◽  
Paola Ferreira Barbosa ◽  
...  
Keyword(s):  
Seismic Anisotropy ◽  
Deformation Mechanisms ◽  
Crustal Rocks ◽  
Central Brazil ◽  
Lower Crustal

The Effect of Secondary Metalworking Processes on Susceptibility of Aircraft to Catastrophic Failures and Prevention Methods

2013 ◽  
Vol 58 (4) ◽  
pp. 1207-1212
Author(s):  
E.S. Dzidowski
Keyword(s):  
Dynamic Recovery ◽  
Fatigue Cracks ◽  
Shear Bands ◽  
Adiabatic Shear ◽  
Deformation Mechanisms ◽  
Processing Maps ◽  
Adiabatic Shear Bands ◽  
Flow Localization ◽  
Catastrophic Failures ◽  
Prevention Methods

Abstract The causes of plane crashes, stemming from the subcritical growth of fatigue cracks, are examined. It is found that the crashes occurred mainly because of the negligence of the defects arising in the course of secondary metalworking processes. It is shown that it is possible to prevent such damage, i.e. voids, wedge cracks, grain boundary cracks, adiabatic shear bands and flow localization, through the use of processing maps indicating the ranges in which the above defects arise and the ranges in which safe deformation mechanisms, such as deformation in dynamic recrystallization conditions, superplasticity, globularization and dynamic recovery, occur. Thanks to the use of such maps the processes can be optimized by selecting proper deformation rates and forming temperatures.

The effect of seismic deformation mechanisms on fluid migration in accumulation area of gold ore concentrations

2019 ◽  
Vol 484 (1) ◽  
pp. 87-92
Author(s):  
T. M. Zlobina ◽  
V. A. Petrov ◽  
K. Yu. Murashov ◽  
A. A. Kotov
Keyword(s):  
Fluid Flow ◽  
Flow Control ◽  
Deformation Mechanisms ◽  
Fluid Migration ◽  
Fluid Regime ◽  
Gold Ore ◽  
Fluid Flow Control ◽  
Seismic Deformation ◽  
Fluid Inflow ◽  
Main Influence

This study investigates the effect of mechanisms of paleode formations during the period of fluid inflow into the accumulation sphere of gold concentrations. Such mechanisms are believed to correspond to DC- and NDC- type seismic mechanisms, whose main influence on fluid migration lies on the formation of different, relative to fluid regime parameters, structural and hydrodynamic organizations of the ore-forming system, and fluid flow control within the area of the accumulation of ore concentrations.  

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