关键词: 四川, 西昌地震, 地表破裂, 地震断层

Abstract: Various earthquake rupture phenomena along the Zemuhe fault were found through field investigation and the age of them was studied by means of lichen measurement, which proves that the surface rupture zone occurred along the Zemuhe fault with a length of at least 90 kilometers during the 1850 earthquake, the maximum horizontal displacement is 7 meters and the maximum vertical displacement is 5.8 meters. The earthquake faulting caused all kinds of geomorphic and geological features, including fault scarps, fault gullies, offset streams and fans, sag ponds, earthquake wedges, landslides and talus etc. According to the scale and the displacement of the earthquake fault along with historical record, it is suggested that the magnitude of the 1850 earthquake should be 8 and the epicentre should be sited at Daqingliangzi, south of Xichang.

Key words: Sichuan, Xichang earthquake, Surface ruptures, Earthquake fault