Systematical Stream Offsets Resulting from Large Earthquakes Along the Strike-Slip Kunlun Fault, Northern Tibetan Plateau: Evidence from the 2001 Mw 7.8 Kunlun Earthquake

ABSTRACT

Field investigations and interpretations of high-resolution remote sensing images reveal geomorphic features of cumulative offsets and deflections of Holocene streams and gullies along the western 450-km segment of the Kunlun fault which triggered the 2001 Mw 7.8 Kunlun earthquake in the northern Tibetan Plateau. The streams and gullies developed on Holocene alluvial fans are sinistrally displaced by up to 115 m, with 3-5 m offsets caused by the 2001 Kunlun earthquake. Radiocarbon ages show that the alluvial fans formed in the past 6,000-9,000 years, suggesting an averaged slip rate of 16±3 mm/yr over the past 6,000-9,000 years on the western 450-km segment of the Kunlun fault. Geomorphic and geologic evidence confirms that the systematical offsets of streams and gullies are the results of repeated large earthquakes and these topographic features are reliable indicators of seismic displacements accumulated on active strike-slip faults

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