This study we trench the Anting bridge no. 3 site in the more south area of the fault scarp that we trenched the no. 1 and no. 2 trenches. This site is lower in relief and it has the advantage of trenching the older paleoseismic events.(figure.1) The sedimentary units in this trench profile is mainly constituted by gravel, and sometimes contains lenticular sand/mud layers. It characterizes the channel and bar environment of alluvial fan system.(figure.2, 3) There are 3 faults in the profile. Attitude of F3 fault is N24°E, 20-35°E, and it cuts through G1 gravel bed and is overlay by O soil. The vertical displacement estimated from the SG3 unit is about 28 cm, and we infer this event as the recent one (1951 coseismic event). F2 fault strikes in N24°E, dips 24-30° to the east, and it cuts through SG1 unit and is overlay by G2 unit. The vertical displacement estimated from the SG1 unit is about 40 cm. F1 fault cutting through the hanging wall of F3 only present in the south wall. Its attitude is N24°E, 25°E, and it cuts through SG1 unit. The vertical displacement estimated from the SG3 unit is about 75 cm. Estimating the coseismic vertical displacement by restoration of deformed bed, we give the value for each event is: F3 is about 45 cm, F2 is about 52 cm, and F1 is about 76 cm. Based on the dated age of the sedimentary unit, we suggest the timing of F1 and F2 events are later than 550-630 yr BP. And the latest event caused by F3 is 1951 coseismic event.

Fig.6-1 The location of Anting bridge no.3 trench.

Fig.6-1 North wall profile of Anting bridge no.3 trench.

Fig.6-2 South wall profile of Anting bridge no.3 trench.