jgg     2014 34 (5):  1-5    ISSN: 0412-1961  CN: 21-1139/TG STUDY ON CRUSTAL DEFORMATION FIELD BEFORE THE “4.20”Ms7  EARTHQUAKE IN LUSHAN，SICHUAN 1）Institute of Geology，CEA，Beijing 100029 2）Tourism and Geographical Sciences，Yunnan Normal University，Kunming 650500 3）National Earthquake Infrastructure Service，Beijing 100063 Received: 2013-08-13  Revised: null  Online: 2014-09-26 Supporting info