- journal_title：Bulletin of the Seismological Society of America
- Contributor：Shunping Pei ; Yongshun John Chen
- Publisher：Seismological Society of America
- Date：2012-
- Format：text/html
- Language：en
- Identifier：10.1785/0120110138
- journal_abbrev：Bulletin of the Seismological Society of America
- issn：0037-1106
- volume：102
- issue：1
- firstpage：445
- section：Short Notes
A high‐resolution 2D (horizontal) seismic velocity model is presented for the upper crust around the epicenter of the 14 April 2010 Ms 7.1 Yushu earthquake from aftershock tomography. The velocity model is obtained using a simple Pn‐like tomography method including both station and event depth corrections. The most striking result is a fast‐velocity anomaly at the epicenter on the Yushu–Garze fault (YGF). The main rupture originated within this fast‐velocity anomaly and propagated southeastward into a slow‐velocity anomaly at Yushu. The second largest aftershock on 29 May 2010 on a nearby fault also occurred within this fast‐velocity anomaly. These results demonstrate a clear example that lateral variation in seismic velocity structures of the upper crust controlled the origination (stress accumulation) and rupture propagation of the 2010 Yushu earthquake and distribution of aftershocks as well. The simple 2D Pg wave travel‐time tomography method presented here introduces a new approach utilizing abundant aftershocks data for investigating the rupturing process of a major earthquake.