Reevaluation of Coseismic Surface Ruptures Produced by the 1850 M 7.5 Xichang Earthquake on the Southeastern Margin of the Tibetan Plateau and Implications for Rupture Propagation at Bends on Strike‐Slip Faults

Estimation of the Nucleation Location and Rupture Extent of the 1850 Xichang, Sichuan, China, Earthquake by Dynamic Rupture Simulations on a Multi‐Segment Stepover Structure

“…The Zemuhe fault was identified as the seismogenic fault of the 1850 Xichang earthquake (Feng et al., 2000; Z. Ren et al., 2010; H. Wang et al., 2018). The Zemuhe fault starts north of Lijinbao, passes through Xichang and Puge, and terminates south of Ningnan, with a fault surface extent of more than 125 km (Figure 1).…”

“…Recently, H. Wang et al. (2018) found new surface ruptures along the Anninghe fault; they emphasized that the Xichang earthquake caused these surface ruptures and that a surface rupture could reach 150 km, spreading from north of Mianning to Puge.…”

“…The 12 September 1850 Xichang earthquake, which occurred on the eastern margin of the Sichuan‐Yunnan block (Wen, Ma, et al., 2008; Y. Wu et al., 2018), is one of the most well‐documented historical earthquakes ever recorded in China (Lin & Gan, 1980). Field observations from different authors give different surface rupture length estimations of this earthquake, ranging from 60 to 150 km; therefore, the magnitude estimate from the above rupture length ranges from 7.3 to 8.0 (Feng et al., 2000; J. Ren & Li, 1993; Z. Ren & Lin, 2010; H. Wang et al., 2018; Wen et al., 2007; Yu et al., 2001). The maximum left‐lateral surface offset was 8 m, which occurred close to Lanbiluo (Du, 2000a; Feng et al., 2000); the maximum intensity of this event was ≥X;, which is deduced from the county annals, epigraphs, and some genealogies (Figure 1; Feng et al., 2000; S. Huang, 1985; Lin & Gan, 1980), and tremendous destruction of houses and buildings and 23,530 deaths were reported in government documents (Feng et al., 2000; Lin & Gan, 1980).…”

“…sketched the intensity distribution of the Xichang earthquake (Figure 1a). Recently, H. Wang et al (2018) investigated the fault interaction between the Zemuhe fault and the northern Anninghe fault during the Xichang earthquake and found that the rupture on the Zemuhe fault may have transferred to the Anninghe fault, even though the strike changed 30° from the Zemuhe fault to the Anninghe fault. By using the empirical Green's function method, Z.…”

“…Field investigations and interpretations of aerial photographs conducted by Z. revealed a relatively short rupture length of 60 km from Qiaowo to the north of Site 1 (Figure 1a). Recently, H. Wang et al (2018) found new surface ruptures along the Anninghe fault; they emphasized that the Xichang earthquake caused these surface ruptures and that a surface rupture could reach 150 km, spreading from north of Mianning to Puge.…”