气候变化领域集成服务门户(CCPortal): Overpressured Underthrust Sediment in the Nankai Trough Forearc Inferred From Transdimensional Inversion of High-Frequency Teleseismic Waveforms

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DOI	10.1029/2020GL088280
	Overpressured Underthrust Sediment in the Nankai Trough Forearc Inferred From Transdimensional Inversion of High-Frequency Teleseismic Waveforms
	Akuhara T.; Tsuji T.; Tonegawa T.
发表日期	2020
ISSN	0094-8276
卷号	47 期号:15
英文摘要	Active-source seismic surveys have resolved the fine-scale P-wave velocity (Vp) of the subsurface structure in subduction forearcs. In contrast, the S-wave velocity (Vs) structure is poorly resolved despite its usefulness in understanding rock properties. This study estimates Vp and Vs structures of the Nankai Trough forearc, by applying transdimensional inversion to high-frequency teleseismic waveforms. As a result, a thin (∼1 km) low-velocity zone (LVZ) is evident at ∼6 km depth beneath the sea level, which is located ~3 km seaward from the outer ridge. Based on its high Vp/Vs ratio (∼2.5) and comparison to an existing seismic reflection profile, we conclude that this LVZ reflects a high pore pressure zone at the upper portion of the underthrust sediment. We infer that this overpressured underthrust sediment hosts slow earthquake activities and that accompanied strain release helps impede coseismic rupture propagation further updip. © 2020. The Authors.
英文关键词	Acoustic wave velocity; Sea level; Seismic waves; Seismology; Shear waves; Wave propagation; Earthquake activity; High frequency HF; Low velocity zones; Rupture propagation; S-wave velocity; Seismic reflection profiles; Subsurface structures; Teleseismic waveforms; Sediments; earthquake rupture; overpressure; P-wave; pore pressure; S-wave; seismic reflection; seismic survey; subduction zone; teleseismic wave; thrust; wave propagation; wave velocity; Nankai Trough; Pacific Ocean
语种	英语
来源期刊	Geophysical Research Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/170017
作者单位	Earthquake Research Institute, The University of Tokyo, Tokyo, Japan; Department of Earth Resources Engineering, Kyushu University, Fukuoka, Japan; Research Institute for Marine Geodynamics, JAMSTEC, Yokohama, Japan
推荐引用方式 GB/T 7714	Akuhara T.,Tsuji T.,Tonegawa T.. Overpressured Underthrust Sediment in the Nankai Trough Forearc Inferred From Transdimensional Inversion of High-Frequency Teleseismic Waveforms[J],2020,47(15).
APA	Akuhara T.,Tsuji T.,&Tonegawa T..(2020).Overpressured Underthrust Sediment in the Nankai Trough Forearc Inferred From Transdimensional Inversion of High-Frequency Teleseismic Waveforms.Geophysical Research Letters,47(15).
MLA	Akuhara T.,et al."Overpressured Underthrust Sediment in the Nankai Trough Forearc Inferred From Transdimensional Inversion of High-Frequency Teleseismic Waveforms".Geophysical Research Letters 47.15(2020).