{"title":"Seismic evidence for a thickened mantle transition zone beneath the Kamchatka subduction zone","authors":"Qinghui Cui , Yuanze Zhou , Yuan Gao , Ran Cui","doi":"10.1016/j.eqs.2025.03.001","DOIUrl":null,"url":null,"abstract":"<div><div>The structures of the mantle transition zone (MTZ) are of great significance for studying interactions of the subducted slab and deep mantle and related slab dynamics beneath subduction zones. Here by dense near-source SdP sampling from a large global dataset, we image topographies of transition zone discontinuities such as the 410-km and 660-km discontinuities (410 and 660) beneath the Kamchatka and conduct cross-section comparisons with the seismicity. Compared with the IASP91 model, the 410 exhibits apparent uplifts of 45−65 km with an average of 55 km in a horizontal width of ∼130 km, corresponding to low-temperature anomalies of 750−1083 K with an average of 916 K. In contrast, the 660 shows depressions of 15−37 km with an average of 25 km together with downward deflections in a width of ∼260 km, implying low-temperature anomalies of 161−397 K with an average of 268 K. Thus, we confirm a thickened MTZ with a thickness of 325−345 km around the cold descending Pacific slab. We suggest that topographic patterns of transition zone discontinuities imply a Pacific slab that has been significantly heated in the MTZ with broadened thermal effects on the 660. When considered along with other studies, we infer that the slab is possibly heated by hot mantle flows around the torn slab window extended to at least the MTZ range, thus inducing variations in thermal and rheological properties of the slab. Our seismic results can provide more insight into slab dynamics in the northwestern Pacific.</div></div>","PeriodicalId":46333,"journal":{"name":"Earthquake Science","volume":"38 4","pages":"Pages 288-303"},"PeriodicalIF":1.2000,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Earthquake Science","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1674451925000199","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"Earth and Planetary Sciences","Score":null,"Total":0}
引用次数: 0
Abstract
The structures of the mantle transition zone (MTZ) are of great significance for studying interactions of the subducted slab and deep mantle and related slab dynamics beneath subduction zones. Here by dense near-source SdP sampling from a large global dataset, we image topographies of transition zone discontinuities such as the 410-km and 660-km discontinuities (410 and 660) beneath the Kamchatka and conduct cross-section comparisons with the seismicity. Compared with the IASP91 model, the 410 exhibits apparent uplifts of 45−65 km with an average of 55 km in a horizontal width of ∼130 km, corresponding to low-temperature anomalies of 750−1083 K with an average of 916 K. In contrast, the 660 shows depressions of 15−37 km with an average of 25 km together with downward deflections in a width of ∼260 km, implying low-temperature anomalies of 161−397 K with an average of 268 K. Thus, we confirm a thickened MTZ with a thickness of 325−345 km around the cold descending Pacific slab. We suggest that topographic patterns of transition zone discontinuities imply a Pacific slab that has been significantly heated in the MTZ with broadened thermal effects on the 660. When considered along with other studies, we infer that the slab is possibly heated by hot mantle flows around the torn slab window extended to at least the MTZ range, thus inducing variations in thermal and rheological properties of the slab. Our seismic results can provide more insight into slab dynamics in the northwestern Pacific.
期刊介绍:
Earthquake Science (EQS) aims to publish high-quality, original, peer-reviewed articles on earthquake-related research subjects. It is an English international journal sponsored by the Seismological Society of China and the Institute of Geophysics, China Earthquake Administration.
The topics include, but not limited to, the following
● Seismic sources of all kinds.
● Earth structure at all scales.
● Seismotectonics.
● New methods and theoretical seismology.
● Strong ground motion.
● Seismic phenomena of all kinds.
● Seismic hazards, earthquake forecasting and prediction.
● Seismic instrumentation.
● Significant recent or past seismic events.
● Documentation of recent seismic events or important observations.
● Descriptions of field deployments, new methods, and available software tools.
The types of manuscripts include the following. There is no length requirement, except for the Short Notes.
【Articles】 Original contributions that have not been published elsewhere.
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【Review Articles】Review articles are by invitation only. Please contact the editorial office and editors for possible proposals.
【Toolboxes】 Descriptions of novel numerical methods and associated computer codes.
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