DOI: 10.1016/j.epsl.2017.10.058
Scopus记录号: 2-s2.0-85033702404
论文题名: Dynamical links between small- and large-scale mantle heterogeneity: Seismological evidence
作者: Frost D.A. ; Garnero E.J. ; Rost S.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 482 起始页码: 135
结束页码: 146
语种: 英语
英文关键词: deep Earth
; mantle dynamics
; mantle structure
; scattering
; seismic arrays
; seismology
Scopus关键词: Array processing
; Earthquakes
; Location
; Scattering
; Velocity
; Deep earths
; Mantle dynamics
; Mantle structure
; Seismic arrays
; Small aperture seismic array
; Small-scale heterogeneity
; Small-scale structures
; Spatial correlations
; Seismology
; heterogeneity
; mantle structure
; seismic tomography
; seismic wave
; seismology
; wave scattering
英文摘要: We identify PKP•PKP scattered waves (also known as P′•P′) from earthquakes recorded at small-aperture seismic arrays at distances less than 65°. P′•P′ energy travels as a PKP wave through the core, up into the mantle, then scatters back down through the core to the receiver as a second PKP. P′•P′ waves are unique in that they allow scattering heterogeneities throughout the mantle to be imaged. We use array-processing methods to amplify low amplitude, coherent scattered energy signals and resolve their incoming direction. We deterministically map scattering heterogeneity locations from the core–mantle boundary to the surface. We use an extensive dataset with sensitivity to a large volume of the mantle and a location method allowing us to resolve and map more heterogeneities than have previously been possible, representing a significant increase in our understanding of small-scale structure within the mantle. Our results demonstrate that the distribution of scattering heterogeneities varies both radially and laterally. Scattering is most abundant in the uppermost and lowermost mantle, and a minimum in the mid-mantle, resembling the radial distribution of tomographically derived whole-mantle velocity heterogeneity. We investigate the spatial correlation of scattering heterogeneities with large-scale tomographic velocities, lateral velocity gradients, the locations of deep-seated hotspots and subducted slabs. In the lowermost 1500 km of the mantle, small-scale heterogeneities correlate with regions of low seismic velocity, high lateral seismic gradient, and proximity to hotspots. In the upper 1000 km of the mantle there is no significant correlation between scattering heterogeneity location and subducted slabs. Between 600 and 900 km depth, scattering heterogeneities are more common in the regions most remote from slabs, and close to hotspots. Scattering heterogeneities show an affinity for regions close to slabs within the upper 200 km of the mantle. The similarity between the distribution of large-scale and small-scale mantle structures suggests a dynamic connection across scales, whereby mantle heterogeneities of all sizes may be directed in similar ways by large-scale convective currents. © 2017 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/110096
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Earth & Planetary Science, University of California, Berkeley, CA, United States; School of Earth and Space Exploration, Arizona State University, Tempe, AZ, United States; Institute of Geophysics and Tectonics, School of Earth and Environment, University of Leeds, Leeds, United Kingdom
Recommended Citation:
Frost D.A.,Garnero E.J.,Rost S.. Dynamical links between small- and large-scale mantle heterogeneity: Seismological evidence[J]. Earth and Planetary Science Letters,2018-01-01,482