Geological and geomorphological evidence of holocene activity along the maisu fault in the northern Sichuan–Yunnan block, Tibetan Plateau

Abstract

The Sichuan–Yunnan block is located in the eastern of Tibetan Plateau and exhibits strong tectonic and earthquake activity. The Maisu fault is an E–W-trending fault within this block. Via interpretations of remote-sensing imagery and field surveys, we identified a earthquake surface rupture zone that has developed along the Maisu fault; we then estimated its Holocene activity. The surface rupture extends westward from the town of Puma, Sichuan Province, to the village of Worilong, Xizang Province, and has a length of approximately 45 km. According to a fault outcrop and carbon-14 dating of a profile near the village of Yongqu, Xizang Province, the most recent earthquake along this rupture may have occurred after 1850 ± 30 BP. The Maisu fault extends eastward and may intersect the Garzê–Yushu fault. Accordingly, as a secondary fault, the Maisu fault likely accommodates the partitioned horizontal slip deformation of the Garzê–Yushu fault.

Holocene activity and seismic surface rupture zone of the Abuduo fault eastern Tibetan Plateau

“…Relevant studies have shown that the slip rate of the Batang fault since the Late Quaternary has been 2.21-3.7 mm/a (Huang et al, 2015;Wang et al, 2015;You et al, 2016), and some studies have suggested that the Batang fault has decomposed the strike-slip deformation of the Garzê-Yushu fault, which has led to change in the slip rate of the Garzê-Yushu fault (Huang et al, 2015;Lv et al, 2017). In addition, related studies also believe that the Maisu fault likely accommodates the partitioned horizontal slip deformation of the Garzê-Yushu fault (Zuo et al, 2022). The Abuduo fault is a leftlateral strike-slip fault with Holocene activity, and its tendency is similar to that of the Batang fault and Maisu fault, i.e., both have near E-W alignment, and the eastward extension of the Abuduo fault is likely to intersect the Garzê-Yushu fault.…”

“…Among the three near E-W-trending faults within the study area, the Batang fault is a left-lateral strike-slip fault with Holocene activity that has had a horizontal slip rate of 2.1-3.9 mm/a since the Late Quaternary, and presents a paleoseismic recurrence cycle of approximately 1,500 years (Huang et al, 2015;You et al, 2016). The Maisu fault is on the southern side of the Garzê-Yushu fault, and geomorphological evidence suggests that it also has Holocene activity, with a predominant left-lateral characteristic (Zuo et al, 2022). Seismological-geomorphological evidence associated with the Abuduo fault also indicates that it is a left-lateral strike-slip fault with Holocene activity, and that it extends eastward to intersect the Garzê-Yushu fault near Zhengke.…”

“…Among them, the Batang fault has been studied for its Late Quaternary activity, slip rate, and tectonic importance (Huang et al, 2015;Wang et al, 2015;You et al, 2016). Zuo et al (2022) undertook research on the geometric structure and Late Quaternary activity of the Maisu fault, and relevant field data on its slip rate have been acquired and are in the process of being compiled. In contrast, other than for some remote sensing image interpretation research, few studies have investigated the Abuduo fault, and field seismological and geological investigation data are notably lacking (Wu et al, 2014;Li et al, 2023).…”