Characteristics of the active Luoshan Fault since Late Pleistocene, North Central China

Abstract

The Luoshan Fault located at the northeastern margin of Tibet plateau strikes roughly N-S, and is composed of
six left-stepping sections with a total length of 60 km. Much evidence suggests that the Luoshan Fault is a reverse
right-lateral strike-slip fault. The largest right-lateral strike-slip displacement and the most abundant dextral
offset phenomena are located along the central section. Based on the right-lateral strike-slip offsets of the oldest
alluvial fan, and of a gully and on the average displacement of the same order of gullies, the minimum slip-rate
has been 2.15 ± 0.2 mm/yr since Late Pleistocene. Many surface rupture phenomena, such as fault scarps with
fresh free-face, ground fissures, displacements of very young gullies, imply that a recent earthquake occurred
along this fault. Combining the historical catalogue and our results, we believe that the 1561 A.D. earthquake
was produced by the Luoshan Fault. Three paleoearthquakes were determined by means of paleoseismic studies
along the Luoshan Fault: they occurred after 8200 ± 600 years BP, between 3130 ± 240 years BP and 4150 ±
± 120 years C.BP, and before 2230 ± 170 years BP, respectively.