High Resolution Crustal Structure Of Datong Volcano From Receiver Function Using Dense Seismic Array

North China Craton(NCC)is one of the most ancient Archean cratons in China.Since the Mesozoic and Cenozoic,the lithosphere of NCC has experienced significant reworking,the eastern NCC has been thinned from over 200 km to less than 100 km,but the western NCC still keeps intact.There are still debates about how the lithosphere of the North China Craton been thinned,the extent,and origin time of the craton destruction.Datong volcanic group is located in the Trans-North China Orogen,the northeastern margin of Ordos.Numerous pervious work using magnetotelluric,P wave and surface wave tomography have found that there are low velocity and high conductivity bodies in the mid-to lower crust and uppermost mantle beneath the Datong volcano.But there are still controversies about the sources of magma that feeds the Datong volcano.In this study,we use seismic data recorded by a dense array deployed by SUSTech in Datong volcano.The The seismic array consists of 166 short-period seismometers,three-component seismometers spaced at 5 Km interval,which are operated for 4 months.We selected 211 well-recorded earthquakes at epicentral distances of 28~0 ～ 92~0,and earthquake magnitude greater than 5.0 to the seismic array.Waveforms from these events were bracketed from 20 s before the first P-wave arrival to 60 s after its arrival and then band-pass filtered between 0.05 and 5.0 Hz,then calculated receive function by Time domain iterative deconvolution,and selected 4541 receivefuntion.We obtain high resolution crustal structure of Datong volcano using H-k stacking and Kirchhoff imaging.The results show that: the crust is relatively thick beneath the western study area,which gradually thins to the east;The Moho depth is fluctuated between 35 and 40 km beneath the Shanxi rift with Vp/Vs ratio in the study area locally up to 2.0.We suggest that the high Vp/Vs ratio is likely caused by the mafic underplating,leading to the conclusion that the crust of the Shanxi rift is not uniformly extended;The thickness of crust gradually decreased from north to south of the study area;To the west of the Datong volcano,relatively thick crust is observed with high Vp/Vs ratio of 1.85.We therefore suggest that mafic underplating mainly exists to the west of the Datong volcano,which supports the hypothesis that the Datong volcano is fed by the asthenospheric upwelling from west.