Paleoseismic observations along the Langshan range-front fault, Hetao Basin, China: Tectonic and seismic implications

Geomorphological signatures of the evolution of active normal faults along the Langshan Mountains, North China

“…Nevertheless, the obtained major channel gradients with high SLK values are mostly concentrated near catchment outlets (Figure 9), suggesting the landscape topography is mostly affected by recent deformation along the range fronts that have low Smf values (<1.4; Figure 6(c)). The tectonic activity of this basin-bounding fault inferred from geomorphological analysis is also verified by the widespread fault scarps mapped in the present (Figures 11-16) and previous active tectonic studies (Dong et al, 2018b;SSB, 1988;Li et al, 2015;Rao et al, 2016Rao et al, , 2018.…”

“…Bagha et al, 2014;Cheng et al, 2018;Delcaillau et al, 1998Delcaillau et al, , 2010El Hamdouni, Irigaray, Fernández, Chacón, & Keller, 2008;Gao, Zeilinger, Xu, Wang, & Hao, 2013;Giaconia et al, 2012;Matoš, Pérez-Peña, & Tomljenović, 2016;Menier et al, 2017; in China (Figure 1(a)), provide excellent chances to investigate tectonic characteristics and geomorphology in actively extending regions (e.g. Deng, 2007;Deng & Liao, 1996;Dong, Zhang, Zhang, Zheng, & Chen, 2018a;Dong et al, 2018b;He, Ma, Long, Wang, & Özkaymak, 2015;Pedrera, Pérez-Peña, Galindo-Zaldívar, Azañón, & Azor, 2009;Pérez-Peña, Azor, Azañón, & Keller, 2010;Wu, Xiao, & Yang, 2014;Yildirim, 2014).…”

“…In contrast to other rift-border faults with earthquakes of M ≥7, there is an obvious lack of historical records about strong earthquakes along the Langshan Piedmont Fault (LPF) bounding the northwest margin of the Hetao Graben (Figures 1 and 2). However, existing paleoseismic data demonstrate that the ~160-km-long LPF has been active during the Holocene and is capable of generating ground-rupturing earthquakes (Dong et al, 2018b;Li, Ran, Chen, Wu, & Lei, 2015;Rao et al, 2016Rao et al, , 2018SSB, 1988). But, it remains unclear whether this major basin-bounding fault moves simultaneously bedrocks and Quaternary sediments, and within the sediments with an average dip of 60° (SSB, 1988;Li et al, 2015;Rao et al, 2018).…”

“…The fault strike changes near its center from ~N35°E to the southwest to ~N50°E to the northeast (Figures 1(c)) and 2). Even if there is no recorded earthquake of M ≥ 7 in the western Hetao Graben (Figure 1(a) and (c); China Earthquake Networks Center [CENC], 2017; Deng, 2007;SSB, 1988;Wen, 2014), recent paleoseismological investigations demonstrated that ground-rupturing earthquakes have occurred on this fault during the Holocene with average recurrence interval of ~2450-2500 years (Dong et al, 2018b;Li et al, 2015;Rao et al, 2016Rao et al, , 2018, and some of them likely had ruptured the whole fault trace (Dong et al, 2018b). Topographically, the high relief and steepness on the southeastern flank of the Langshan Mountains are in contrast to the gentler slopes on its northwestern flank as revealed by the 5-km wide ridge-perpendicular swath profiles ( Figure 3).…”

Segmented Thrust Faulting: Example From the Northeastern Margin of the Tibetan Plateau

“…Few studies examine the relationship of fault segmentation and growth to individual earthquake ruptures and slip rates, due to the density of data such studies require. As with fault growth, examples focus on normal faults, along which slip history is well preserved in landforms and paleoseismology (e.g., Dong et al, ; Machette et al, ).…”