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Title: Understanding Depth Variation of Deep Seismicity from in situ Measurements of Mineral Strengths at High Pressures

Abstract

Strengths of major minerals of Earth's mantle have been measured using in situ synchrotron X-ray diffraction at high pressures. Analysis of the diffraction peak widths is used to derive the yield strengths. Systematic analysis of the experimental result for olivine, wadsleyite, ringwoodite and perovskite indicates that minerals in the upper mantle, the transition zone and the lower mantle have very distinct strength character. Increasing temperature weakens the upper mantle mineral, olivine, significantly. At high temperature and high pressure, the transition zone minerals, wadsleyite and ringwoodite, have higher strengths than the upper mantle mineral. Among all the minerals studied, the lower mantle mineral, perovskite, has the highest strength. While both the upper mantle and the transition zone minerals show a notable strength drop, the strength of the lower mantle mineral shows just an increase of relaxation rate (no strength drop) when the temperature is increased stepwise by 200 K. The strength characteristics of these major mantle minerals at high pressures and temperatures indicate that yield strength may play a crucial role in defining the profile of deep earthquake occurrence with depth.

Authors:
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
DOE - OFFICE OF SCIENCE
OSTI Identifier:
1019937
Report Number(s):
BNL-95783-2011-JA
Journal ID: ISSN 0022-3697; JPCSAW; TRN: US201115%%573
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Journal Name:
Journal of Physics and Chemistry of Solids
Additional Journal Information:
Journal Volume: 71; Journal Issue: 8; Journal ID: ISSN 0022-3697
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; DIFFRACTION; EARTHQUAKES; INORGANIC COMPOUNDS; MECHANICAL PROPERTIES; OLIVINE; PEROVSKITE; RELAXATION; SEISMICITY; SYNCHROTRONS; X-RAY DIFFRACTION; YIELD STRENGTH; national synchrotron light source

Citation Formats

Chen, J. Understanding Depth Variation of Deep Seismicity from in situ Measurements of Mineral Strengths at High Pressures. United States: N. p., 2010. Web. doi:10.1016/j.jpcs.2010.03.001.
Chen, J. Understanding Depth Variation of Deep Seismicity from in situ Measurements of Mineral Strengths at High Pressures. United States. doi:10.1016/j.jpcs.2010.03.001.
Chen, J. Fri . "Understanding Depth Variation of Deep Seismicity from in situ Measurements of Mineral Strengths at High Pressures". United States. doi:10.1016/j.jpcs.2010.03.001.
@article{osti_1019937,
title = {Understanding Depth Variation of Deep Seismicity from in situ Measurements of Mineral Strengths at High Pressures},
author = {Chen, J.},
abstractNote = {Strengths of major minerals of Earth's mantle have been measured using in situ synchrotron X-ray diffraction at high pressures. Analysis of the diffraction peak widths is used to derive the yield strengths. Systematic analysis of the experimental result for olivine, wadsleyite, ringwoodite and perovskite indicates that minerals in the upper mantle, the transition zone and the lower mantle have very distinct strength character. Increasing temperature weakens the upper mantle mineral, olivine, significantly. At high temperature and high pressure, the transition zone minerals, wadsleyite and ringwoodite, have higher strengths than the upper mantle mineral. Among all the minerals studied, the lower mantle mineral, perovskite, has the highest strength. While both the upper mantle and the transition zone minerals show a notable strength drop, the strength of the lower mantle mineral shows just an increase of relaxation rate (no strength drop) when the temperature is increased stepwise by 200 K. The strength characteristics of these major mantle minerals at high pressures and temperatures indicate that yield strength may play a crucial role in defining the profile of deep earthquake occurrence with depth.},
doi = {10.1016/j.jpcs.2010.03.001},
journal = {Journal of Physics and Chemistry of Solids},
issn = {0022-3697},
number = 8,
volume = 71,
place = {United States},
year = {2010},
month = {1}
}