气候变化领域集成服务门户(CCPortal): Amplification and Tuning of Ground Motion at the Outer Cascadia Accretionary Prism

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DOI	10.1029/2020JB020950
	Amplification and Tuning of Ground Motion at the Outer Cascadia Accretionary Prism
	Davis E.E.; Farrugia J.J.
发表日期	2021
ISSN	21699313
卷号	126 期号:5
英文摘要	Ground-motion amplification in the outer Cascadia subduction zone accretionary prism has been documented previously by comparing earthquake and microseismic vertical ground-motion and pressure records from an ONC/NEPTUNE Canada cabled observatory site on the outer prism to those from a site on the flank of the Juan de Fuca Ridge. Since then, four additional instruments became operational, and data, now spanning 10 years, include more than 100 large (Mw > 7) distant earthquakes. Well-tuned response at the outer prism sites is observed in both vertical and horizontal components, with peaks in the spectral ratio of vertical velocity relative to nearby ocean crustal and continental bedrock sites (V/Vref) at 9 s, and in the intra-site horizontal to vertical spectral ratio horizontal-to-vertical spectral ratio at 14 s, both with band widths of ±10% to 15% at half amplitude. The vertical response is consistent with ¼ wavelength compressional wave reinforcement, while the horizontal motion tuning most likely reflects the effects of the low velocity prism sediments on surface-wave propagation. At the periods of maximum relative motion, outer prism surface-wave vertical and horizontal accelerations are enhanced by factors of up to 15 and 25, respectively. Similar behaviour is seen in microseismic records from these sites, and, to a lesser extent, in earthquake records from temporarily deployed Cascadia Initiative seismometers along the outer Cascadia prism to the south. Such tuning and amplification must be accounted for when assessing the dynamic behavior of the prism and its basal fault at the time of large local earthquakes. © 2021. American Geophysical Union. All Rights Reserved.
英文关键词	accretionary prisms; seismic resonance; seismology; site response; subduction zones; Vp/Vs ratio
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187094
作者单位	Pacific Geoscience Centre, Geological Survey of Canada, Sidney, BC, Canada
推荐引用方式 GB/T 7714	Davis E.E.,Farrugia J.J.. Amplification and Tuning of Ground Motion at the Outer Cascadia Accretionary Prism[J],2021,126(5).
APA	Davis E.E.,&Farrugia J.J..(2021).Amplification and Tuning of Ground Motion at the Outer Cascadia Accretionary Prism.Journal of Geophysical Research: Solid Earth,126(5).
MLA	Davis E.E.,et al."Amplification and Tuning of Ground Motion at the Outer Cascadia Accretionary Prism".Journal of Geophysical Research: Solid Earth 126.5(2021).