jgg     2013 33 (3):  1-4    ISSN: 0412-1961  CN: 21-1139/TG STUDY ON 3-D VELOCITY STRUCTURE BY TEMPORARY DENSE  SEISMOSTATIONS NETWORKS OF TANGSHAN EARTHQUEKE REGION Geophysical Exploration Center, CEA, Zhengzhou 450002 Received: 2012-09-21  Revised: null  Online: 2013-06-18 Supporting info