The unequal distribution of volcanic products between the Earth-facing lunar side and the farside is the result of a complex thermal history. The Chang'e-4 mission targeted the Moon's farside, landing on the floor of Von Kármán crater (VK) inside the South Pole-Aitken (SPA) basin. This paper presents the first deep subsurface stratigraphic structure based on ground-penetrating radar (GPR) data from the Yutu-2 rover. The radargram reveals at least four layers of distinct lava flows, likely from the Imbrium Epoch, with thicknesses ranging from 12 m to 100 m, indicating multiple lava-infilling events within VK crater. The average loss tangent of mare basalts is estimated at 0.0040-0.0061.

Jialong Lai, Yi Xu, Roberto Bugiolacchi, Xu Meng, Long Xiao, Minggang Xie, Bin Liu, Kaichang Di, Xiaoping Zhang, Bin Zhou, Shaoxiang Shen, Luyuan Xu