New constraints for slip rates along the Altyn Tagh fault, northwestern Tibet Plateau

Abstract

Based on ¹⁰Be dating of offset terraces at two sites, fieldwork, and high-resolution topographic analysis, we obtained the Holocene slip rates along the central section of the Altyn Tagh fault (ATF). At the Alesayi site, the minimum slip rate is confined to 6.4–11.6 mm/yr since 6.0 ± 1.4 ka. At the Suman site, the slip rate is confined to 5.6–9.2 mm/yr since 7.6 ± 0.7 ka. Eventually, the slip rate is tightly bracketed from 6.4 to 9.2 mm/yr, which implies that the microplate model with localized deformation between rigid blocks should be abandoned. Synthesis of late Quaternary slip rates along the fault indicates that the central section, except for restraining bends, maintains a constant slip rate of ∼10 mm/yr. The long elapsed time, ∼400 years, since the most recent earthquake and a significant stress increase resulting from the 2014 Ms7.3 Yutian earthquake led to a high seismic risk along the central fault section.