The Tancheng-Lujiang fault zone is the largest deep fault zone in eastern China. The 8700 local seismic events recorded by the network across Jiangsu, Anhui, Shandong, Shanghai and Zhejiang Province are relocated. We developed a multiphase traveltime inversion (MUTT) algorithm to inverse crust velocity structure. The 3-D velocity structute beneath the :Shandong-Jiangsu-Anhui segment of the Tancheng-Lujiang fault zone and adjacent areas was imaged by seismic tomography. The result shows that the crust can be divided into upper, middle and lower crust. We found the following features: (1) There are evident velocity differences among different tectonic units in the research area: lower velocities in the lower Yangtze fault block, intermediate in the China-Korean fault block, and higher in the Dabie-Sulu block. (2) The P-velocities of UHPM belt are higher than adjacent areas in the upper crust and lower crust, especially at depths of 5 similar to 15 km; (3) There are low-velocity areas in the range of 30 degrees similar to 36 degrees N, 115 degrees similar to 124 degrees E at depths 20 similar to 25 km. There is spatial correlation between lower velocity areas and major earthquakes. (4) The Moho depths are deeper in the southwest and shallower in the northeast. (5) The velocity structure of the Tancheng-Lujiang fault zone in the research area exhibits segmentation, and velocity differences exist among various tectonic units, which indicate that the Tancheng-Lujiang fault zone is a boundary among different geological blocks.
