GEOCHEMICAL FEATURES OF LONGMENSHAN FRACTURES AFTER WENCHUAN EARTHQUAKE

Based on the field measurement of the main fault of Longmenshan structral belt after the earthquake, the Radon concentration measurement's data is processed and analyzed, and three main faults' activities are compared. The result shows that the ratio of Radon viscosity's maximum and background value along the front fault is around 3.5～7.1, in which the ratio in the segment with surface rupture is 7.0～7.1, while the one without surface rupture ranges from 3.5 to 5.6; the ratio of central fracture and back range fracture are around 7.05～8.75 and 7.3 respectively. That means the central range fracture has the stronger activity than the others, which suggests that the seismic-fault of the earthquake is the central one and the other faults' movement were triggered by it. At the same time, the fault along the Tongji-Baishuihe bridge was stimulated by the central fracture, the ratio is 6.05.