A widespread mid-crustal low-velocity layer beneath Northeast China revealed by the multimodal inversion of Rayleigh waves from ambient seismic noise. (1st July 2020)

• Record Type: Journal Article
• Authors: Zhan, Wang; Pan, Lei; Chen, Xiaofei
• Is Part Of: Journal of Asian earth sciences. Volume 196(2020)
• Publication Date: 2020-07-01
• Subjects: Low-velocity layer in middle crust -- Rayleigh wave dispersion -- Higher modes -- Dispersion curves inversion -- 3D crustal model -- Northeast China; Earth sciences -- Asia -- Periodicals; Sciences de la terre -- Asie -- Périodiques; Earth sciences; Asia; Periodicals; 555.05
• DOI: 10.1016/j.jseaes.2020.104372
• Languages: English
• ISSNs: 1367-9120

Abstract

Graphical abstract: Highlights: F-J method was applied to analyzing ambient seismic noise data recorded in NE China. Higher-modes Rayleigh waves dispersion curves were extracted from ambient seismic noise data. Application of multi-modes made inversion results more robust and accurate. A high-resolution 3D crustal Vs model of NE China was obtained by inversion of multi-modal dispersion curves. A widespread mid-crustal LVL beneath NE China was revealed by the inversion. Abstract: In this study, we re-examined the crustal and uppermost mantle shear velocity structure beneath Northeast China using the broadband ambient seismic noise data from several temporary and permanent arrays in this region. By employing our newly developed interferometric analysis method (F-J method) for array noises and the corresponding multi-mode dispersion curve inversion approach, we obtained an integrated crustal and uppermost mantle shear velocity model of this region. We divided the study area into 39 overlapping sub-areas and then applied the F-J method to each sub-area to obtain a 3D shear velocity model. We extracted the fundamental mode and up to 4 higher-mode dispersion curves of Rayleigh waves in frequencies ranging 0.02–0.45 Hz from the ambient seismic noise data, inverted multi-mode dispersion curves, and obtained local 1D shear velocity model for each sub-area. By integrating all 1D shear velocity models of the 39 overlapping sub-areas, we obtained a 3D crustal and upper mantle model of Northeast China. Our integrated 3D model shows a widely distributed low-velocity zone at a depth of approximately 10–20 km located beneath the northern part of Xing-Mong orogenic belt and Songliao basin and the Changbaishan Mountain. Moreover, a large high-velocity zone underneath the region around the northern edge of Songliao basin is observed at a depth of approximately 40–50 km depth. These results provide evidence to improve our understanding of the tectonics of Northeast China.