Slip Rate and Paleoseismology of the Bolokenu‐Aqikekuduk (Dzhungarian) Right‐Lateral Strike‐Slip Fault in the Northern Tian Shan, NW China

Abstract

AbstractThe ∼1,000 km‐long Bolokenu‐Aqikekuduk fault (Dzhungarian fault, BAF) is one of the major right‐lateral strike‐slip faults that cut across the Tian Shan Range. Although the BAF plays an important role in accommodating crustal shorting of the Tian Shan and cuts through densely populated cities, little is known about its late Quaternary tectonic activity or earthquake history. Here we quantify the late Quaternary dextral strike‐slip rate of the BAF along the Jinghe segment based on interpretation of high‐resolution remote sensing images and structure‐from‐motion (SfM)‐derived DEMs, field observations and the abandonment ages of displaced alluvial fans, which were constrained by optically stimulated luminescence (OSL) and cosmogenic 10Be depth profile dating methods. Using the offset of fan risers and gullies incised into the fan surfaces, we yielded a right‐lateral strike‐slip rate of 3.2 + 1.4/−1.1 mm/a. Compared with the entire crustal shortening rates across the Tian Shan, the BAF accommodates ∼23% of the N‐S crustal shortening rate. Additionally, a paleoseismic trench reveals four events since the late Pleistocene with an average recurrence time of ∼4–6 ka. The last event occurred after ∼6.6 ka, which is slightly larger than the average recurrence time, suggesting that the BAF represents a potential high seismic risk for the densely populated area nearby.