A New Perspective on Fault Geometry and Slip Distribution of the 2009 Dachaidan Mw 6.3 Earthquake from InSAR Observations

Sensors

Yang Liu¹  Caijun Xu¹  Yangmao Wen¹  Hok Sum Fok¹ 

[1] School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, China; E-Mails:

关键词: InSAR;    fault geometry;    slip distribution;    the 2009 Dachaidan Mw 6.3 earthquake;    the Tibet Plateau;    rupture propagation;   

DOI  :  10.3390/s150716786

来源: mdpi

【 摘 要 】

On 28 August 2009, the northern margin of the Qaidam basin in the Tibet Plateau was ruptured by an Mw 6.3 earthquake. This study utilizes the Envisat ASAR images from descending Track 319 and ascending Track 455 for capturing the coseismic deformation resulting from this event, indicating that the earthquake fault rupture does not reach to the earth’s surface. We then propose a four-segmented fault model to investigate the coseismic deformation by determining the fault parameters, followed by inverting slip distribution. The preferred fault model shows that the rupture depths for all four fault planes mainly range from 2.0 km to 7.5 km, comparatively shallower than previous results up to ~13 km, and that the slip distribution on the fault plane is complex, exhibiting three slip peaks with a maximum of 2.44 m at a depth between 4.1 km and 4.9 km. The inverted geodetic moment is 3.85 × 10¹⁸ Nm (Mw 6.36). The 2009 event may rupture from the northwest to the southeast unilaterally, reaching the maximum at the central segment.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.