Eikonal surface wave tomography of central and eastern China

SUMMARY Eikonal tomography has become a key approach to image lithospheric structures with surface waves recorded by dense regional arrays. Its main advantage is that phase velocities can be determined directly from measurements without resolving tomographic inverse problem. Here, we apply new smoothing spline eikonal selection of 40 large (Mw larger than 6.5) teleseismic events the permanent seismic stations CEArray. We first time–frequency filter isolate fundamental mode Rayleigh and cross-correlate cleaned isolated wave records measure precise relative traveltimes. The are then unwrapped corrected for cycle skipping. Finally, derive phase-velocity maps gradient reconstructed traveltime fields, using equation. obtain finely resolved 25 150 s period inverted 3-D shear velocity model which in good agreement previous studies. architecture emerging S-wave correlates geology major tectonic provinces. In particular, narrow rift systems, South China Craton, North Craton (NCC) revealed unprecedented details. characterized very high beneath Sichuan Basin. NCC shows more complex two high-velocity anomalies Ordos Basin southeastern low-velocity Cenozoic systems.