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Small‐Scale Intraslab Heterogeneity Weakens Into the Mantle Transition Zone

Shen, Zhichao and Zhan, Zhongwen and Jackson, Jennifer M. (2021) Small‐Scale Intraslab Heterogeneity Weakens Into the Mantle Transition Zone. Geophysical Research Letters, 48 (23). Art. No. e2021GL094470. ISSN 0094-8276. doi:10.1029/2021gl094470.

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Small-scale intraslab heterogeneity is well documented seismically in multiple subduction zones, but its nature remains elusive. Previous efforts have been mostly focusing on the scattering strength at intermediate depth (<350 km), without constraining its evolution as a function of depth. Here, we illustrate that the inter-source interferometry method, which turns deep earthquakes into virtual receivers, can resolve small-scale intraslab heterogeneity in the mantle transition zone. The interferometric waveform observations in the Japan subduction zone require weak scattering (<1.0%) within the slab below 410 km. Combining with previous studies that suggest high heterogeneity level (∼2.5%) at intermediate depth, we conclude that the small-scale intraslab heterogeneity weakens as slabs subduct. We suggest that the heterogeneities are caused by intraslab hydrous minerals, and the decrease in their scattering strength with depth reveals processes associated with dehydration of subducting slabs.

Item Type:Article
Related URLs:
URLURL TypeDescription ItemSeismic data - Hi-net ItemSeismic data - F-net ItemInternational Seismological Centre ItemNational Research Institute for Earth Science and Disaster Resilience
Shen, Zhichao0000-0003-0458-5264
Zhan, Zhongwen0000-0002-5586-2607
Jackson, Jennifer M.0000-0002-8256-6336
Additional Information:© 2021. American Geophysical Union. Issue Online: 24 November 2021. Version of Record online: 24 November 2021. Accepted manuscript online: 16 November 2021. Manuscript accepted: 10 November 2021. Manuscript revised: 09 November 2021. Manuscript received: 26 May 2021. The authors are grateful to Mike Gurnis, Rob Clayton, and two anonymous reviewers for discussions and suggestions. The authors are grateful to the National Science Foundation's (NSF) Collaborative Study of Earth's Deep Interior under EAR-2009935 for support of this work. Data Availability Statement. Seismic data are collected from Hi-net ( and F-net ( The earthquake catalog and focal mechanisms are downloaded from ISC-EHB distributed by the International Seismological Centre ( and National Research Institute for Earth Science and Disaster Resilience (NIED;
Group:Seismological Laboratory
Funding AgencyGrant Number
Issue or Number:23
Record Number:CaltechAUTHORS:20211209-231098000
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Official Citation:Shen, Z., Zhan, Z., & Jackson, J. M. (2021). Small-scale intraslab heterogeneity weakens into the mantle transition zone. Geophysical Research Letters, 48, e2021GL094470.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:112340
Deposited By: George Porter
Deposited On:10 Dec 2021 19:55
Last Modified:01 Feb 2022 22:56

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