Mantle Tomography of Central-Eastern USA: Influence of Inversion Volume Size

doi:10.1029/2022JB024782

	Liang, Xuran 1,2,3; Zhao, Dapeng 4; Hua, Yuanyuan 1,2,5; Xu, Yi-Gang1,2,3,5
	Mantle Tomography of Central-Eastern USA: Influence of Inversion Volume Size
刊名	JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
ISSN号	2169-9313
	2022-12-01
卷号	127 期号:12 页码:18
DOI	10.1029/2022JB024782
语种	英语
WOS研究方向	Geochemistry & Geophysics
摘要	Teleseismic tomography is a powerful tool to study the 3-D structure of the upper mantle beneath a local seismic network, but the robustness of its images has been challenged by the increasing size of the study volume in recent studies. This is because teleseismic tomography uses relative travel-time residuals (RTTRs) that are contaminated more by the whole-mantle heterogeneity for a larger study region. In this work, we correct the RTTRs of teleseismic events for the mantle heterogeneities outside the study volume using two global tomographic models. Our results show that the whole-mantle correction is necessary when a study region is wider than similar to 10 degrees, and the maximum outside residual reaches 1.2 s for a study region of similar to 35 degrees wide. After the whole-mantle correction, those teleseismic events with a large ray spread angle are still useful for tomographic imaging. Applying this approach to teleseismic travel-time data recorded by the USArray, we obtain a high-resolution 3-D P-wave velocity (Vp) model beneath the central and eastern United States. It shows three low-velocity anomalies beneath the New Madrid Seismic Zone, the East Tennessee Seismic Zone, and the South Carolina Seismic Zone, suggesting that lithospheric weakness induced by fluids may play an important role in reactivating the intraplate seismic zones. The passage of the Bermuda hotspot and remnants of the subducted Farallon slab in the lower mantle might be responsible for the fluid release and lithospheric weakening, which reactivated ancient rifts and suture zones in the crust and facilitated the formation of the intraplate seismic zones. Plain Language Summary Teleseismic tomography is a widely used method exploiting travel-time data of distant earthquakes to study the three-dimensional seismic velocity structure of the upper mantle beneath a study region covered by a seismograph network. We find that the size of the study volume significantly affects teleseismic tomography and the data should be corrected for the whole-mantle heterogeneity outside the study volume. We obtain a reliable tomographic model beneath the central and eastern US by making the whole-mantle correction to high-quality travel-time data of teleseismic events recorded by the USArray seismic network. Our results reveal three low-velocity anomalies beneath the New Madrid Seismic Zone, the East Tennessee Seismic Zone, and the South Carolina Seismic Zone in the central and eastern US, as well as remnants of the subducted Farallon plate in the lower mantle under the region. Hot and wet mantle upwelling flow may contribute to reactivation of ancient rifts and suture zones, which can cause the intraplate seismic zones. In addition, the passage of the Bermuda hotspot and the deeply subducted Farallon plate may have facilitated the formation of the three intraplate seismic zones.
WOS记录号	WOS:000924589600001
收录类别	SCI
引用统计	被引频次：6[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.gig.ac.cn/handle/344008/69909
专题	同位素地球化学国家重点实验室
通讯作者	Liang, Xuran; Zhao, Dapeng
作者单位	1.Chinese Acad Sci, State Key Lab Isotope Geochem, Guangzhou Inst Geochem, Guangzhou, Peoples R China 2.Chinese Acad Sci, CAS Ctr Excellence Deep Earth Sci, Guangzhou Inst Geochem, Guangzhou, Peoples R China 3.Univ Chinese Acad Sci, Sch Earth & Planetary Sci, Beijing, Peoples R China 4.Tohoku Univ, Grad Sch Sci, Dept Geophys, Sendai, Miyagi, Japan 5.Southern Marine Sci & Engn Guangdong Lab Guangzho, Guangzhou, Peoples R China
推荐引用方式 GB/T 7714	Liang, Xuran,Zhao, Dapeng,Hua, Yuanyuan,et al. Mantle Tomography of Central-Eastern USA: Influence of Inversion Volume Size[J]. JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,2022,127(12):18.
APA	Liang, Xuran,Zhao, Dapeng,Hua, Yuanyuan,&Xu, Yi-Gang.(2022).Mantle Tomography of Central-Eastern USA: Influence of Inversion Volume Size.JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,127(12),18.
MLA	Liang, Xuran,et al."Mantle Tomography of Central-Eastern USA: Influence of Inversion Volume Size".JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH 127.12(2022):18.