气候变化领域集成服务门户(CCPortal): Dynamic Upwelling Beneath the Salton Trough Imaged With Teleseismic Attenuation Tomography

CCPortal

DOI	10.1029/2020JB020347
	Dynamic Upwelling Beneath the Salton Trough Imaged With Teleseismic Attenuation Tomography
	Byrnes J.S.; Bezada M.
发表日期	2020
ISSN	21699313
卷号	125 期号:11
英文摘要	The Salton Trough is one of the few regions on Earth where rifting is subaerial instead of submarine. We use the relative attenuation of teleseismic P phases recorded by the Salton Trough Seismic Imaging Project to investigate lithospheric and asthenospheric structures that form during extension. Map-view analysis reveals stronger attenuation within the Salton Trough than in the adjacent provinces. We then construct tomographic models for variations in seismic attenuation with depth to discriminate between crustal and mantle signals with a damped least squares approach and a Bayesian approach. Synthetic tests show that models from damped least squares significantly underestimate the strength of attenuation and cannot separate crustal and mantle signals even if the tomographic models are allowed to be discontinuous at the lithosphere-asthenosphere boundary (LAB). We show that a Bayesian approach overcomes these problems when inverting the same synthetic data sets and that shallow and deep signals are more clearly separated when imposing a discontinuity. With greater than 95% confidence, the results reveal first, that attenuation occurs primarily beneath the LAB; second, that the width of the attenuative region is narrower than the rift at 120 km depth; and third, that the strength of attenuation requires that the attenuative feature represents a melting-column similar to those beneath mid-ocean ridges. The narrow width of the melting column below the volatile-free solidus is inconsistent with models for passive upwelling, where flow is driven only by rifting. Instead, we attribute the generation of incipient oceanic crust to mantle upwelling focused by buoyancy into a narrow diapir. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	attenuation; Bayesian; mantle flow; P waves; Salton Trough; tomography
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/187488
作者单位	Department of Earth Sciences, University of Minnesota, Minneapolis, MN, United States
推荐引用方式 GB/T 7714	Byrnes J.S.,Bezada M.. Dynamic Upwelling Beneath the Salton Trough Imaged With Teleseismic Attenuation Tomography[J],2020,125(11).
APA	Byrnes J.S.,&Bezada M..(2020).Dynamic Upwelling Beneath the Salton Trough Imaged With Teleseismic Attenuation Tomography.Journal of Geophysical Research: Solid Earth,125(11).
MLA	Byrnes J.S.,et al."Dynamic Upwelling Beneath the Salton Trough Imaged With Teleseismic Attenuation Tomography".Journal of Geophysical Research: Solid Earth 125.11(2020).