Slip Rate Variation Along the Kunlun Fault (Tibet): Results From New GPS Observations and a Viscoelastic Earthquake‐Cycle Deformation Model

The slip rate and its spatial variations of the Kunlun fault (KLF) play important roles in the tectonic evolution of the northeastern Tibetan Plateau. Here the slip rate of the Tuosuo Lake (TL) segment of the KLF, which remains controversial from various geological observations, is investigated with a dense Global Positioning System observation profile. With a viscoelastic earthquake‐cycle deformation model, the slip rate of the TL segment is estimated to be 5.5 ± 0.7 mm/a , in comparison with an overestimated value of 9.2 ± 1.1 mm/a from an elastic model. Combined with previous results, we infer that the slip rate of the KLF likely decreases gradually from the TL segment toward the eastern tip, rather than remaining uniform along the fault or decreasing rapidly within the easternmost 150 km. The estimated lower crust viscosity (~ 10 18 Pa · s ) agrees with values inferred from postseismic studies, which suggests a weak ductile lower crust in this region.