The Research On The Impact Of Displacement Field Of Japan 3.11 Earthquake Of Tan-lu Fault Zone

Tanlu-fault zone is a large fault belt in eastern China in our country, and it experienced multiphase tectonic fracture.The falut is not only a deep fault zone composed of shear movement,but also a fault zone that still inherited the neotectonic movement forms in recent years and predominantly dextral reverse, as well as a range with activity degree,obvious seismic zone. From ancient to now,a series of geological activities have never been interrupted in both sides of the Tan-lu zone and its nearby area.On March 11, 2011, a large magnitude 9.0 earthquake occurred on the Pacific waters on east of sendai, and it epicenter is about 24 km.This earthquake is the largest earthquake in Japan’s history,and it caused devastation in some cities.Both Japan and eastern region of China are the confluence of Eurasian plate, Pacific plate and Philippine plate, which have homologous in background, the subduction of the Pacific to Eurasian plate is one of the important power source of seismic activity in the east of China.In December 2004, the earthquake in Indonesia’s Sumatra have led to the 2000 kilometers of sichuan-yunnan region seismicity increasing obviously in our country.In history,the Tan-lu fault occurred Tan Cheng 8.5 magnitude earthquake in 1668 and Hai Cheng 7.3 magnitude earthquake in 1975,so how much impact the Japan earthquake will have to the Tan-lu fault is a concern.In this paper, we use the finite element numerical simulation method to explore the influence of Japan 3.11 earthquake to Tan-lu fault zone in our country, the specific research work as follows:(1)According to the actual geological data, the finite element model one covering about 1050 square kilometers is established, and then make the constraint of model boundary condition according to the observed data of GPS, finally compared the simulation results to the actual measured value to verify the feasibility of the simulation method.(2)In order to improve the simulation precision, we selected the paragraph which is the strongest earthquake in Tan-lu fault and named it as model two,and then mesh it with more precise.After that,we simulate the model according to the actual measured data,at last we give the corresponding conclusions according to the simulation results.Experiments show that the impact of Japan earthquake on China’s northeast area are significantly greater than in north China,the coseismic displacement of the northeast of China even reached more than 30 mm. At the same time, there are obvious difference in both sides of the fault zone.It indicated that the fault has obvious delay to the displacement.(3)After the 3.11 earthquake, earthquake occured very frequent in matsubara swarm, we simulate displacement field of this area and calculate the coulomb stress.Through calculation results of coulomb stress changes, we discussed the possibility of future earthquake.(4) We simulated the displacement changes of Tan-lu in Shandong and the experiment shows that the east-west displacement in shandong region is hign in east and low in west,the change of gradient is balanced;however,the displacement both in X and Y direction has a emergence gradient changes in Linyi-Weifang of the Tan-lu fault.we found that the stress and strain values in this eara have more apparent rotation based on vector.We conclude that in the future,the seismic risk of Weifang-Linyi area in Tan-lu fault should cause us more attention.Innovation points:(1) the range of geological model not only contains the epicenter and its nearby area,but also extended to the areas far from the source and the model covers more than 1050 spuare kilometers,which can make sure the scientific of the results.(2) The experiments are conducted in the latest version of ANSYS platform, the model of meshing is more delicate compared to other specialists, which can obviously improve the precision of the calculation.(3) The constraint of the model boundary conditions were fully carried out in accordance with the actual earthquake seismogenic data, we comprehensively compared the simulation results to the GPS data, which can ensure the reliablity of the simulation results.