Reconstructing and quantifying fault slip is essential for better understanding of the dynamics of faulting and seismic hazard assessment (Avouac, 2015;Harris, 2017). Distinguishing and estimating seismic or aseismic fault slip on geologic timescales (specifically ∼10 1−4 years) is challenging due to the lack of historical, geodetic, remote sensing data extending beyond a few decades or centuries. Moreover, seismic or aseismic slip record in landform and sedimentary archives over such timescales is often incomplete because geologic processes, including later earthquakes, which may destroy the evidence of earlier earthquakes (McCalpin & Nelson, 2009). However, bedrock fault scarps provide one of the best archives for studying past earthquakes and determining the nature and rates of fault slip because they are resistant to erosion and relate directly to a particular fault.Over the past few decades, exposure histories of bedrock fault scarps have been inferred by methods based on the accumulation of terrestrial cosmogenic nuclides (TCNs; Williams et al., 2017;Zreda & Noller, 1998). However, these methods have significant challenges for earthquakes with short recurrence intervals that lay within the uncertainty of the dating and the difficulties of measuring the extremely low concentrations of TCNs in young (10 1−2 years) bedrock fault scarps (Zreda & Noller, 1998). Moreover, it is hard to distinguish discontinuous points in the profiles of TCN concentration versus fault scarp height because the fault displacements for some

The Permo-Triassic period marks the time interval between Hercynian (Variscan) orogenic events in the Tien Shan and the North Pamir, and the Cimmerian accretion of the Gondwana-derived Central and South Pamir to the southern margin of the Paleo-Asian continent. A well-preserved Permo-Triassic volcano-sedimentary sequence from the Chinese North Pamir yields important information on the geodynamic evolution of Asia’s pre-Cimmerian southern margin. The oldest volcanic rocks from that section are dated to the late Guadalupian epoch by a rhyolite and a dacitic dike that gave zircon U-Pb ages of ~260 Ma. Permian volcanism was largely pyroclastic and mafic to intermediate. Upsection, a massive ignimbritic crystal tuff in the Chinese Qimgan valley was dated to 244.1±1.1 Ma, a similar unit in the nearby Gez valley to 245±11 Ma, and an associated rhyolite to 233.4±1.1 Ma. Deposition of the locally ~200 m thick crystal tuff unit follows an unconformity and marks the onset of intense, mainly mafic to intermediate, calc-alkaline magmatic activity. Triassic volcanic activity in the North Pamir was coeval with the major phase of Cimmerian intrusive activity in the Karakul-Mazar arc-accretionary complex to the south, caused by northward subduction of the Paleo-Tethys. It also coincided with the emplacement of basanitic and carbonatitic dikes and a thermal event in the South Tien Shan, to the north of our study area. Evidence for arc-related magmatic activity in a back-arc position provides strong arguments for back-arc extension or transtension and basin formation. This puts the Qimgan succession in line with a more than 1000 km long realm of extensional Triassic back-arc basins known from the North Pamir in the Kyrgyz Altyn Darya valley (Myntekin formation), the North Pamir of Tajikistan and Afghanistan, and the Afghan Hindukush (Doab formation) and further west from the Paropamisus and Kopet Dag (Aghdarband, NE Iran).