Evaluating the resolution of deep mantle plumes in teleseismic traveltime tomography
File(s)
Author(s)
Maguire, Ross
Ritsema, Jeroen
Bonnin, Mickaël
Goes, S
Van Keken, Peter
Type
Journal Article
Abstract
The strongest evidence to support the classical plume hypothesis comes from seismic imaging of the mantle beneath hot spots. However, imaging results are often ambiguous and it is questionable whether narrow plume tails can be detected by present-day seismological techniques. Here we carry out synthetic tomography experiments based on spectral element method simulations of seismic waves with period T > 10 s propagating through geodynamically derived plume structures. We vary the source-receiver geometry in order to explore the conditions under which lower mantle plume tails may be detected seismically. We determine that wide-aperture (4,000–6,000 km) networks with dense station coverage (<100–200 km station spacing) are necessary to image narrow (<500 km wide) thermal plume tails. We find that if uncertainties on traveltime measurements exceed delay times imparted by plume tails (typically <1 s), the plume tails are concealed in seismic images. Vertically propagating SKS waves enhance plume tail recovery but lack vertical resolution in regions that are not independently constrained by direct S paths. We demonstrate how vertical smearing of an upper mantle low-velocity anomaly can appear as a plume originating in the deep mantle. Our results are useful for interpreting previous plume imaging experiments and guide the design of future experiments.
Date Issued
2017-11-23
Date Acceptance
2017-11-18
Citation
Journal of Geophysical Research, 2017, 123 (1), pp.384-400
ISSN
0148-0227
Publisher
American Geophysical Union
Start Page
384
End Page
400
Journal / Book Title
Journal of Geophysical Research
Volume
123
Issue
1
Copyright Statement
©2017. American Geophysical Union. All Rights Reserved.
Subjects
Science & Technology
Physical Sciences
Geochemistry & Geophysics
seismic tomography
computational seismology
hot spots and mantle plumes
wave scattering and diffraction
wave propagation
MULTIPLE-FREQUENCY TOMOGRAPHY
WAVE-FORM INVERSION
PHASE-EQUILIBRIA
NORTH-AMERICA
BENEATH
ICELAND
MODEL
ZONE
HETEROGENEITY
YELLOWSTONE
Publication Status
Published
Date Publish Online
2018-01-10