Revisiting Late Quaternary Slip-rate along the Maqu Segment of the Eastern Kunlun Fault, Northeast Tibet

The Late Quaternary slip rate along the Maqu segment of the eastern Kunlun Fault was estimated using a combination of high-resolution remote sensing imagery interpretation, field observations and differential Global Positioning System (GPS) measurements of offset river terraces, and C-14 dating of snail shells collected from offset risers. The results show that the left-slip rate along the segment is 3-5 mm/a, and that the vertical slip rate is 0.3-0.5 mm/a. Both the horizontal and vertical slips on the segment remain consistent over a distance of approximate to 100 km. It means that no slip gradient as previously suggested occurred along the Maqu segment, and which thus might behave as an independent seismogenic fault. Judging from multiple relationships among young terrace offsets, we infer that co-seismic surface rupture produced by a characteristic earthquake with a magnitude of Ms7.0-7.5 on the Maqu fault could generate a horizontal slip of 4.5-5 m and a vertical slip of 0.45-0.5 m, with a corresponding ratio (Dh/Dv) of about 9. Two surface rupture events must have occurred over the past 3300 years, the latest one possibly between 1485 cal BP and 1730 cal BP.