The 14 November 2001, M-w = 7.8 Kunlunshan earthquake ruptured the westernmost part of the Kunlun Fault, northern Tibetan Plateau. The main segment affected by this event was the Kusaihu segment. Field investigations allowed us to constrain the length, the width, and the coseismic horizontal displacement distribution of the Kunlunshan earthquake rupture zone. The mapped surface rupture zone starts from 90.257 degrees E in the west and ends at 94.795 degrees E in the east with a total length of 426 km. It consists of three main sections, the western strike-slip section, the transtensional section, and the eastern strike-slip section. The rupture zone is oriented N100 degrees +/- 10 degrees E on average. The distribution of the coseismic horizontal displacements is characterized by multiple peaks departing clearly from a general bell-shaped distribution. Reassessment of the maximum coseismic horizontal left-lateral displacement yields a value of 7.6 +/- 0.4 m at the site (35.767 degrees N, 93.323 degrees E) consistent with independent measurements derived from interferometric synthetic aperture radar and seismology. From this site the horizontal displacement decreases unevenly to both the west and east. Coseismic vertical ( reverse) displacement is also noted at the eastern end of the rupture but it remains much smaller than the horizontal component. The width of the rupture zone varies from site to site from several meters to few kilometers. The maximum width measured reaches 8 km along the Yuxi Feng subsection where a large number of shaking related cracks were well developed.
China Erathquake Adm, Inst Geol, Beijing 100029, Peoples R China; Inst Phys Globe, F-75005 Paris, France; Inst Phys Globe, F-67084 Strasbourg, FranceArticleEnglish