Paleoseismic activity on Wujiahe segment of Serteng piedmont fault, Inner Mongolia

Abstract

Geomorphic study on Wujiahe segment of Serteng piedmont fault, Inner Mongolia is made. Through analysis of the available data in combination with the results of predecessors' studies it can be obtained that average vertical displacement rate is 0.48-0.75 mm/a along the Wujiahe segment since the late Pleistocene (14.450~22.340 ka BP) and 0.56--0.88 mm/a since the early-middle Holocene (5.570--8.830 ka BP). Analyzing paleoseismic phenomena revealed in the excavated 5 trenches in combination with the results of predecessors' studies of paleoearthquakes on the fault, we determine five paleoseismic events on the Wujiahe segment of Serteng piedmont fault since 27.0 ka BP and the recurrence interval to be about 4.300~4.400 ka. A cluster of paleoearthquakes occurred probably during 8.000-9.000 ka BP and two paleoseismic events in 10.000-20.000 ka BP may be missed. A comparison between height of fault scarps and sum of displacement caused by paleoseismic events revealed in trenches, and recurrence interval of paleoseismic events obtained from average displacement rate along the fault and the dislocation by one event suggest that three paleoseismic events are absent in Alagaitu trench. Two paleoseismic events may be absent on the whole active fault segment.

Holocene stratigraphic sequences in the northern Ordos Plateau and its implications for the disappearance of Huoluochaideng ancient city in the Han Dynasty, North China

“…Those faults are mainly normal faults that once had been active in history period and led to great earthquakes with M ≥ 6.0 (Deng, Zhang, & Ran, 2003;Deng & Liao, 1996;Rao, Chen, Hu, Yu, & Qiu, 2016;Rao et al, 2018;Wesnousky, Jones, Scholz, & Deng, 1984;Zhang, Yang, Zhong, & Mi, 1995 (Shen et al, 2016). The slip rate of the Langshan Mountain piedmont fault at 1.43-1.62 mm/year demonstrates the strong activity since Pleistocene and the most recent earthquake may have occurred in~1,880 with the maximum magnitude of Mw 7.8 Rao et al, 2016Rao et al, , 2018 Many studies on the Serteng Mountain piedmont fault have been reported, including the tectonic activity of this fault (He, Ma, Long, Wang, & Zhang, 2018;Yang, Ran, Hu, & Guo, 2002;Yang, Ran, Guo, & Hu, 2003), ground fissures (He et al, 2017), slip rates (Zhang et al, 2017), and geometric patterns (Rao et al, 2019). Yang et al (2002Yang et al ( , 2003 identified at least five palaeoearthquake events of surface rupture type which were associated with the Seerteng Mountain piedmont fault since the Holocene (~10.3-7.7 ka BP,~7-6 ka BP,~5.57 ka BP,~4.5-3.9 ka BP, and~3.5-3 ka BP).…”

“…The slip rate of the Langshan Mountain piedmont fault at 1.43-1.62 mm/year demonstrates the strong activity since Pleistocene and the most recent earthquake may have occurred in~1,880 with the maximum magnitude of Mw 7.8 Rao et al, 2016Rao et al, , 2018 Many studies on the Serteng Mountain piedmont fault have been reported, including the tectonic activity of this fault (He, Ma, Long, Wang, & Zhang, 2018;Yang, Ran, Hu, & Guo, 2002;Yang, Ran, Guo, & Hu, 2003), ground fissures (He et al, 2017), slip rates (Zhang et al, 2017), and geometric patterns (Rao et al, 2019). Yang et al (2002Yang et al ( , 2003 identified at least five palaeoearthquake events of surface rupture type which were associated with the Seerteng Mountain piedmont fault since the Holocene (~10.3-7.7 ka BP,~7-6 ka BP,~5.57 ka BP,~4.5-3.9 ka BP, and~3.5-3 ka BP). He et al (2018) The Langshan Mountain piedmont fault and Seerteng Mountain piedmont fault and intersected at a large angle at Langshankou, which form the northwest boundary of the Linhe Sag in the Hetao Basin (Dong, 2017;Jiang, 2003;Yang et al, 2002Yang et al, , 2003.…”

“…Yang et al (2002Yang et al ( , 2003 identified at least five palaeoearthquake events of surface rupture type which were associated with the Seerteng Mountain piedmont fault since the Holocene (~10.3-7.7 ka BP,~7-6 ka BP,~5.57 ka BP,~4.5-3.9 ka BP, and~3.5-3 ka BP). He et al (2018) The Langshan Mountain piedmont fault and Seerteng Mountain piedmont fault and intersected at a large angle at Langshankou, which form the northwest boundary of the Linhe Sag in the Hetao Basin (Dong, 2017;Jiang, 2003;Yang et al, 2002Yang et al, , 2003. The Langshan and Seerteng Mountains have been uplifted since the Oligocene and show strong vertical movements during the Quaternary.…”

“…The Langshan and Seerteng Mountains have been uplifted since the Oligocene and show strong vertical movements during the Quaternary. Fault topography such as fault cliff, fault scarps, and third stages of platforms are well developed in the northern margin of the Hetao Basin due to the activity of these faults (Dong, 2017;Jiang, 2003;Yang et al, 2002Yang et al, , 2003.…”

“…The fault could be divided into four segments: Langshankou and Hongqicun segments and the Kuoluebulong and Dashetai segments (He et al, 2017). Many studies on the Serteng Mountain piedmont fault have been reported, including the tectonic activity of this fault (He, Ma, Long, Wang, & Zhang, 2018; Yang, Ran, Hu, & Guo, 2002; Yang, Ran, Guo, & Hu, 2003), ground fissures (He et al, 2017), slip rates (Zhang et al, 2017), and geometric patterns (Rao et al, 2019). Yang et al (2002, 2003) identified at least five palaeoearthquake events of surface rupture type which were associated with the Seerteng Mountain piedmont fault since the Holocene (~10.3–7.7 ka BP, ~7–6 ka BP, ~5.57 ka BP, ~4.5–3.9 ka BP, and ~3.5–3 ka BP).…”