Detailed mapping of the surface rupture of the 12 February 2014 Yutian M_s7.3 earthquake,Altyn Tagh fault,Xinjiang,China

作者：Zhaode YUAN,Jing LIU-ZENG,Xue LI,Jing XU,Wenqian YAO,Longfei HAN,Tao LI

摘要：Large-scale detailed mapping plays a key role in revealing the rupture characteristics and mechanisms of strong earthquakes.Relatively few studies have been performed on the surface ruptures of large earthquakes in central and western Tibet due to its remote nature and high elevation.Based on high-resolution unmanned aerial vehicle(UAV)photography,we mapped the coseismic surface rupture of the 2014 Yutian M_s7.3 earthquake.Along the western Altyn Tagh fault system,the earthquake produced~37 km of surface rupture along the South Xor Kol fault(southern section S1),Xor Kol fault(central section S2)and Ashikule fault(northern section S3).Section S1 has a 16-km-long surface rupture with an average sinistral offset of 52±25 cm and a maximum offset of~90 cm,while section S3 has a 14.2-km-long surface rupture with an average sinistral offset of 36±21 cm and a maximum offset of~84 cm.A compilation of 5308 cracks yields an average crack width along the southern section of 85±71 cm and a maximum width of~700 cm;the average width along the central section is 39±21 cm,and the maximum width is 243 cm;and the average width along the northern section is 61±44 cm with a maximum of~340 cm.In addition,the average cumulative opening across rupture zone is 3.4±2.9 m along the southern section,with a maximum of~17 m;4.3±3.6 m along the central section,with a maximum of~13 m;and 1.7±1.6 m along the northern section,with a maximum of~6 m.Evidently,the average crack width and cumulative opening decrease towards bends and steps along the fault.A global synthesis of surface rupture distributions corresponding to strike-slip earthquakes indicates that the rupture zone is wider near the complex parts of fault geometries(such as bends,steps and fault bifurcations)than along straight sections,suggesting that the fault geometry has an obvious control on the surface rupture width.The widespread cracks at the intersection between the Xor Kol and South Xor Kol faults may indicate that an extensional regime is more likely to produce distrib

发文机构：State Key Laboratory of Earthquake Dynamics School of Earth System Science Key Laboratory of Earthquake Geodesy

关键词：AltynTaghfaultYutianearthquakeCoseismicsurfaceruptureGravity-drivenslideCoseismicoffsetSurfacerupturewidth

分类号： P31[天文地球—固体地球物理学]