2. Historical earthquakes
Together with the Altyn Tagh, Ganzi-Yushu-Xianshuhe, and Kunlun faults,
the Qilian-Hiayuan fault system consists of the tectonic boundaries of
the north and northeastern Tibet (Peltzer et al., 1988; Tapponnier et
al., 2001). With the continuing south-north convergence between India
and Eurasia plates, deformation along these major boundary strike-slip
faults accommodates the eastward extrusion of the Tibetan Plateau by
generating frequent large earthquakes in northeastern Tibet (Meyer et
al., 1998; Wang et al., 2001). Geodetic data indicates that slip rates
vary along the approximately 1000 km long Qilian-Haiyuan fault system,
which are 1-2 mm/a, 4-6 mm/a, 3.4-6.4mm/a, 2.9-5.6mm/a, and 5 mm/a on
the HLHF; TLSF; LLLF; JQHF-MMSF-LHSF, and HYF , respectively (Wang et
al., 2020).
During the past century, the eastern Qilian-Haiyuan fault system
generated 5 large earthquakes (M ≥ 5.9): 1990 Mw 6.2 Tianzhu (No. 7),
1986 Mw 6.0 Menyuan (No. 8), 2016 Mw 5.9 Menyuan (No. 9), 1920 Mw 8.5
(No. 10) Haiyuan, and 2022 Mw 6.6 Menyuan earthquakes (No. 12) (Tang and
Wang, 1993; Liu-Zeng et al., 2007, 2015; Zhang et al., 2020; Peng et
al., 2021; Yang et al., 2022). According to historical earthquake
document, 7 historical large earthquake (M ≥ 7.0) occurred within the
horizontal distance of less than 300 km from the Qilian-Haiyuan fault
system from 1920 to 2022. This includes the 1932 Mw 7.5 Changma (No. 1),
1954 Mw 7.3 Shandan (No. 2), 1954 Mw 7.0 Minqin (No. 3), 1937 Tuosuo
Lake (No. 4), 1963 Alake Lake (No. 5), 1990 Mw 7.0 Gonghe (No. 6), and
1927 Mw 8.5 Gulang earthquakes (Nos. 11) (Molnar and Deng, 1984;
Gaudemer et al., 1995; Liu and Fu, 2001; Wan et al., 2007; Xu et al.,
2002) (Figure 1). The detailed earthquake parameters are summarized in
Table S1 (Supporting Information Text S1). In total, 12 historical
earthquakes (Nos. 1-12 in Figure 1) were included in the ΔCFS
calculations in this study.