Earthquake Characteristics
The earthquake rupture began on a relatively small strike-slip fault segment at the western end of the Kunlun fault in the region of the mountain Buka Daban Feng. The rupture propagated to the east via an extensional stepover before following the main strand of the Kunlun fault. The region of co-seismic deformation (i.e. that occurred during the earthquake) is unusually large, with significant faulting being observed up to 60 km from the main rupture trace. This deformation occurs in two swathes, ca. 20 and 60 km from the main fault trace. Pre-existing lineaments and geomorphological features suggest that this earthquake-triggered displacement occurred on existing faults.
An analysis of the propagation speed indicates that the rupture propagated at a normal velocity along the original segment, but increased in velocity to above the S-wave velocity after the jump across the extensional stepover and continued at that speed until propagation stopped. This makes the Kunlun earthquake the best documented example of a supershear earthquake. It has been suggested that the unusually wide zone of co-seismic deformation is a direct result of the supershear rupture propagation.
Read more about this topic: 2001 Kunlun Earthquake
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