DOI: 10.1016/j.epsl.2021.117036
论文题名: Changes in elastic wave velocity during brittle deformation of gabbro and peridotite: Implications for oceanic Moho reflectivity
作者: Akamatsu Y. ; Katayama I. ; Tonegawa T.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2021
卷: 568 语种: 英语
中文关键词: dilatancy
; elastic wave velocity
; gabbro
; oceanic Moho
; peridotite
; synthetic seismogram
英文关键词: Deformation
; Elastic waves
; Reflection
; Rocks
; Strain rate
; Wave propagation
; Brittle deformation
; Dilatancy
; Elastic wave velocity
; Gabbro
; Gabbroic rocks
; Maximum stress
; Oceanic lithosphere
; Oceanic moho
; Peridotite
; Synthetic seismogram
; Seismology
; brittle deformation
; confining pressure
; deformation
; elastic wave
; gabbro
; Moho
; oceanic lithosphere
; peridotite
; seismogram
; strain rate
; wave velocity
英文摘要: Cracks that develop during brittle deformation easily modify rocks' physical properties; therefore, understanding of seismic properties of oceanic rocks during deformation is essential for interpretation of the seismic observations of the oceanic lithosphere. Here we measured elastic wave velocities of gabbro and peridotite during triaxial deformation experiments at room temperature, a confining pressure of 20 MPa, and a strain rate of ∼10−6 s−1. Gabbroic rocks showed significant decrease in elastic wave velocities approaching the maximum stress, which is comparable to that of typical crystalline rocks. On the other hand, peridotite showed relatively sudden and small decrease in elastic wave velocities close to the maximum stress. We inverted the observed velocities to crack density tensor based on an effective medium theory. The different changes in elastic wave velocities between gabbroic rocks and peridotites were interpreted by different characteristics of crack development, where limited number of cracks were opened in peridotite than in gabbroic rocks. The calculated reflection coefficient of the interface between the gabbro and peridotite increases from <0.1 to ∼0.25 as approaching the maximum stress. Synthetic seismograms computed from the crack-dependent velocity structures of the oceanic lithosphere indicate that the Moho reflectivity is highly sensitive to the contrast of crack-damage across the crust-mantle boundary. The existence of a heterogeneous crack-damaged zone in the oceanic lithosphere, which is likely related to intra-plate earthquakes, may result in the spatial variations of Moho reflection. © 2021 The Author(s) Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165395
Appears in Collections: 气候变化与战略
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作者单位: Department of Earth and Planetary Systems Science, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan; Research Institute for Marine Geophysics, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, 236-0001, Japan
Recommended Citation:
Akamatsu Y.,Katayama I.,Tonegawa T.. Changes in elastic wave velocity during brittle deformation of gabbro and peridotite: Implications for oceanic Moho reflectivity[J]. Earth and Planetary Science Letters,2021-01-01,568