Kilometer-scale structure on the core–mantle boundary near Hawaii
Li, Zhi; Leng, Kuangdai; Jenkins, Jennifer; Cottaar, Sanne
Dr Jenny Jenkins email@example.com
The lowermost mantle right above the core-mantle boundary is highly heterogeneous containing multiple poorly understood seismic features. The smallest but most extreme heterogeneities yet observed are ‘Ultra-Low Velocity Zones’ (ULVZ). We exploit seismic shear waves that diffract along the core-mantle boundary to provide new insight into these enigmatic structures. We measure a rare core-diffracted signal refracted by a ULVZ at the base of the Hawaiian mantle plume at unprecedentedly high frequencies. This signal shows remarkably longer time delays at higher compared to lower frequencies, indicating a pronounced internal variability inside the ULVZ. Utilizing the latest computational advances in 3D waveform modeling, here we show that we are able to model this high-frequency signal and constrain high-resolution ULVZ structure on the scale of kilometers, for the first time. This new observation suggests a chemically distinct ULVZ with increasing iron content towards the core-mantle boundary, which has implications for Earth’s early evolutionary history and core-mantle interaction.
Li, Z., Leng, K., Jenkins, J., & Cottaar, S. (2022). Kilometer-scale structure on the core–mantle boundary near Hawaii. Nature Communications, 13(1), https://doi.org/10.1038/s41467-022-30502-5
|Journal Article Type||Article|
|Acceptance Date||Apr 28, 2022|
|Online Publication Date||May 19, 2022|
|Deposit Date||Aug 1, 2022|
|Publicly Available Date||Aug 1, 2022|
|Peer Reviewed||Peer Reviewed|
Published Journal Article
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