Activity Characteristics and Safety distance of Gaoliying Ground Fissure in Beijing Haigang Wang, Tongchun Qin, Haipeng Guo, Juyan Zhu, Yunlong Wang, Xisheng Zang and Xia Li E3S Web Conf., 79 (2019) 02009 Published online: 15 January 2019 DOI: 10.1051/e3sconf/20197902009