Joint‐Rupture Pattern and Newly Generated Structure of Fault Intersections on the Northern Margin of the Linhe Basin, Northwestern Ordos Block, China

Abstract

The Ordos Block is located northeast of the Tibetan Plateau (Figure 1a; Deng et al., 1999). Since the Cenozoic, due to the rapid expansion of the Tibetan Plateau to the northeast (Gaudemer et al., 1995;Tapponnier et al., 1982Tapponnier et al., , 1986 and subduction of the Pacific plate to the west (Northrup et al., 1995;Uyeda & Kanamori, 1979), at least four M ≥ 8 large earthquakes have been triggered in the basin on the periphery of the Ordos Block. These earthquakes were the 1303 Hongdong M 8.0 earthquake in the Shanxi Basin in the eastern block

Classification and Semiquantitative Evaluation of Paleoearthquake Identification From Trenches on Normal Faults: A Case Study of Holocene Paleoearthquake Events From the Northern Margin of the Hetao Basin, China

“…Liang et al. (2022) collected 23 paleoseismic trenches of the Sertengshan and Langshan piedmont faults and concluded that seven events had occurred since the Holocene between the two faults and were consistent with the characteristics of quasiperiodic recurrence, which was essentially consistent with our conclusion. However, we clearly gave the identification indicators of each event, which improves the objectivity and logic of the paleoearthquake event determination.…”

“…Comparison of the maximum displacement of the Holocene paleoearthquake events and cumulative displacement showed that the two are essentially consistent; therefore, the paleoearthquake series of the Sertengshan Daqingshan piedmont faults since the Holocene are complete. Liang et al (2022) collected 23 paleoseismic trenches of the Sertengshan and Langshan piedmont faults and concluded that seven events had occurred since the Holocene between the two faults and were consistent with the characteristics of quasiperiodic recurrence, which was essentially consistent with our conclusion. However, we clearly gave the identification indicators of each event, which improves the objectivity and logic of the paleoearthquake event determination.…”

“…Liang et al. (2022) revealed two paleoearthquake events in the Dongwugaigou Trench; Event 1 occurred later than 2.44 ± 0.03 ka, and Event 2 occurred slightly earlier than 5.45 ± 0.03 ka. The latest event revealed by Rao et al.…”

“…EL1 is jointly defined by the Dongwugaigou Trench (TS1) and Fanrong Trench (TS2). Liang et al (2022) revealed two paleoearthquake events in the Dongwugaigou Trench; Event 1 occurred later than 2.44 ± 0.03 ka, and Event 2 occurred slightly earlier than 5.45 ± 0.03 ka. The latest event revealed by Rao et al (2016) in the Fanrong Trench occurred from 1.88 ± 0.03 to 2.05 ± 0.03 ka.…”

“…Among these trenches, the Delingshan Trench (TS9) (He et al, 2017) was excavated in a ground fissure, revealing the latest event, EK1 (<1.51 ± 0.2 ka), on the Kuluebulong segment. By comparing the paleoearthquake events on the Sertengshan and Langshan segments, Liang et al (2022) concluded that EK2 (<2.32 ± 0.29 ka) was an M8 earthquake event that occurred in 7 BCE and argued that this event caused the Langshan and Sertengshan piedmont faults along the Langshankou and Kuluebulong segments to form multisegment ruptures. The Dongshuiquan Trench (TS10) (He et al, 2018) and Dongfengcun Trench (TS11) (Yang et al, 2002) revealed a total of four other paleoearthquake events, that is, EK3 (3.11 ± 0.25-3.56 ± 0.11 ka), EK4 (3.56 ± 0.11-4.53 ± 0.36 ka), EK5 (<5.77 ± 0.11 ka), and EK6 (10.45 ± 0.32-10.55 ± 0.82 ka).…”