气候变化领域集成服务门户(CCPortal): The Northern Gulf Anomaly: P- and S-wave travel time delays illuminate a strong thermal feature beneath the Northern Gulf of Mexico

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DOI	10.1016/j.epsl.2020.116102
	The Northern Gulf Anomaly: P- and S-wave travel time delays illuminate a strong thermal feature beneath the Northern Gulf of Mexico
	Krauss Z.; Menke W.
发表日期	2020
ISSN	0012821X
卷号	534
英文摘要	Seismic measurements are used in a detailed investigation of a region of extremely low asthenospheric seismic velocities along the US Gulf Coast, first imaged in continental-scale geotomography, which we term the Northern Gulf Anomaly (NGA). Differential P- and S-wave arrival times from teleseisms at a variety of back-azimuths, observed on EarthScope Transportable Array stations near the US Gulf Coast, demonstrate that asthenospheric seismic velocities are 8-10% lower than the neighboring craton, and define the spatial extent and character of the anomaly. Travel time anomalies are calculated relative to the AK135 earth model and corrected to account for the effect of the kilometers-thick sedimentary cover in the region. The NGA is most intense at the southernmost coast of Louisiana and East Texas (with an eastern edge at 89°W) and smoothly tapers away in a triangular wedge that extends inland as far as 300 km. It has sharper edges and a smaller areal extent (by ∼50%) than previously-published geotomography has indicated. Both the magnitude and ratio of delays indicate that the NGA has a thermal origin, which may represent past or present-day small-scale convective upwelling near the southeastern edge of the North American continent. The NGA suggests that large-scale but poorly understood asthenospheric processes are at work beneath the US Gulf Coast, notwithstanding this region's reputation as an aseismic, passively-subsiding continental margin. © 2020 Elsevier B.V.
关键词	asthenospheric upwelling EarthScope Transportable Array edge-driven convection Gulf of Mexico USArray
英文关键词	Group delay; Seismic waves; Seismology; Time delay; asthenospheric upwelling; Continental margin; EarthScope Transportable Array; Gulf of Mexico; Northern Gulf of Mexico; Seismic measurements; Seismic velocities; USArray; Shear waves; anomaly; arrival time; asthenosphere; convection; craton; P-wave; S-wave; seismic tomography; seismic velocity; travel time; upwelling; Atlantic Ocean; Gulf Coast [United States]; Gulf of Mexico; United States
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202707
作者单位	Lamont-Doherty Earth Observatory, 61 Rte 9W, Palisades, NY 10964, United States
推荐引用方式 GB/T 7714	Krauss Z.,Menke W.. The Northern Gulf Anomaly: P- and S-wave travel time delays illuminate a strong thermal feature beneath the Northern Gulf of Mexico[J],2020,534.
APA	Krauss Z.,&Menke W..(2020).The Northern Gulf Anomaly: P- and S-wave travel time delays illuminate a strong thermal feature beneath the Northern Gulf of Mexico.Earth and Planetary Science Letters,534.
MLA	Krauss Z.,et al."The Northern Gulf Anomaly: P- and S-wave travel time delays illuminate a strong thermal feature beneath the Northern Gulf of Mexico".Earth and Planetary Science Letters 534(2020).