Evaluating Global Tomography Models With Antipodal Ambient Noise Cross‐Correlation Functions. Issue 3 (5th March 2021)

• Record Type: Journal Article
• Authors: Xie, Jun; Chu, Risheng; Ni, Sidao
• Is Part Of: Journal of geophysical research. Volume 126:Issue 3(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-03-05
• Subjects: ambient noise cross‐correlation functions -- antipodal surface waves -- mantle heterogeneity -- tomography model evaluation; Geomagnetism -- Periodicals; Geochemistry -- Periodicals; Geophysics -- Periodicals; Earth sciences -- Periodicals; 551.1
• DOI: 10.1029/2020JB020444
• Languages: English
• ISSNs: 2169-9313

Abstract

Abstract: It is essential to evaluate global tomography models, which provide important information for understanding Earth's structure and dynamics. Long‐period surface waves propagating between antipodal stations are good candidates for this purpose since they depend on global‐scale velocity variations in the upper mantle. In this study, we extract minor‐arc and major‐arc Rayleigh waves from ambient noise cross correlations between GEOSCOPE station AIS and ∼1, 800 USArray stations near the antipode of AIS. We identify two Rayleigh‐wave‐focusing regions and simulate the observed maximum amplitude pattern at the antipodal region using synthetic surface waves based on three global tomography models. Our simulations suggest that seismic heterogeneity of the tomography models need to be inflated by a factor of 2–3 in oceanic regions to explain the observed focusing pattern of surface waves near the antipodal region. Key Points: Anomalous focusing patterns are observed in the surface waves from ambient noise cross correlation at the antipodal region Main patterns of the maximum amplitude of minor‐arc or major‐arc Rayleigh waves include two focusing regions near the antipode Current global tomography models are proposed to have underestimated heterogeneity in regions not well sampled