Paleoseismic evolution of the central section of the Serteng Shan fault at the northern Ordos Block (North China) since the Late Pleistocene

Abstract

ABSTRACT Reliable palaeoseismological data are crucial for understanding the rupture history and seismic hazard assessment of a specific seismogenic structure. Many large earthquakes occurred around the Ordos Block of northern China. However, due to insufficient age data and event interpretations, the rupture patterns of the block are still poorly known. This study focuses on the central section of the Serteng Shan fault that is situated at the north margin of the Ordos Block. We present palaeoseismic sequence of faults using trenches combined with dating methods, including optically stimulated luminescence and 14C dating. We collected eleven optically stimulated luminescence (OSL) and seven radiocarbon samples to constrain the timing of palaeoseismic events in the excavated trench exposures along the fault strand. The results show that the studied samples were deposited since the latest Pleistocene, and the ages are, within uncertainty, in the stratigraphic order. The cause of the most recent surface rupture is still not clear. Four other older events, which occurred in 3.1–3.9 ka, 5.8−6.5 ka, 10.8–13.1 ka, and 14.2–16.5 ka, likely extended at different lengths along the Serteng Shan fault.