This study presents the results of the Rayleigh wave group velocity tomography in North\udChina performed using ambient seismic noise observed at 190 broadband and 10 very broadband\udstations of the North China Seismic Array. All available vertical component time-series\udfor the 14 months between 2007 January and 2008 February are cross-correlated to obtain\udempirical Rayleigh wave Green’s functions that are subsequently processed, with the multiple\udfilter method, to isolate the group velocity dispersion curves of the fundamental mode of the\udRayleigh wave. Tomographic maps, with a grid spacing of 0.25◦ × 0.25◦, are computed at\udperiods of 4.5, 12, 20 and 28 s. The maps at short periods reveal lateral heterogeneity in the\udcrust of North China, in good agreement with known geological and tectonic features. The\udNorth China Basin is imaged as a broad low velocity area, while the Taihangshan and Yanshan\uduplifts and Ordos block are imaged as high velocity zones, and the Quaternary intermountain\udbasins show up as small low-velocity anomalies. A well-defined low velocity zone in the\udBeijing–Tianjin–Tangshan region is observed at 28 s period. The low velocity zone may be\udassociated with the upwelling of hot mantle material. The group velocity maps at 4.5, 12 and\ud20 s are consistent with Bouguer gravity anomalies measured in the area of the Taihangshan\udfault, that cuts through the lower crust at least.
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