Fine structure of the Moho discontinuity under the Datong volcanic field inferred from a short-period ultra-dense seismic array

To better understand the deep structure and geodynamics of the Datong volcanic field, we apply the receiver-function CCP stacking method to investigate the Moho depth variations in the study area. We use continuous teleseismic waveforms recorded by an ultra-dense, short-period seismic array consisting of 291 stations with an average inter-station distance of ∼5 km, which were deployed for ∼40 days during August to September 2023. After the sedimentary layer correction, detailed depth variations of the Moho discontinuity are revealed beneath the 191 stations in the study area. Our results show that the Moho depth across the entire study area ranges from ∼36 to 44 km. Beneath the Liulengshan mountain, the Moho is relatively deep, reaching a depth of ∼42 km. There are significant variations in the Moho depth on both sides of the Liulengshan piedmont fault. In contrast, beneath the Datong volcanic area, the Moho is, notably shallower, at depths of ∼36 to 40 km. Additionally, the Moho is significantly shallow in a NW-SE oriented zone, which is well consistent with the Datong volcanic field, and there is a nearly E-W shallow Moho zone, which is required to further investigate. The Moho depth variations may be related to the upwelling of hot asthenospheric material, which may lead to the crustal thinning. The hot material upwelling may be related to the India-Asia collision and the combined effects of the westward subduction of the Pacific plate and a deep mantle plume. Our results shed new light on the deep origin and geodynamic processes of the Datong volcanoes.