Research On Analysis Of The Active Faults And Three-dimensional Model In Linfen Based On Multi-source Data

The active fault is the main cause of direct earthquake disaster in the city. The research of active faults provides the basis for the government to make the earthquake prevention and disaster reduction, so it is closely related to people’s life and property safety.This paper selects Linfen in Shanxi Province as the study area, then analyzes the activity of faults in the study area based on field observation, drilling, geophysical exploration,geochemical exploration and trenching data and builds 3D model of active faults by comprehensive utilization of the analysis results and active fault exploration data. This model combines faults with strata and is used for spatial analysis and 3D visualization display in this paper. The main research contents and results are as follows:(1) Analyze the distribution and the latest active age of major faults in the study area.This paper analyzes the distribution of faults and how they cut strata and modifies the position of faults based on drill hole data, shallow seismic data and drill hole data on the joint section. By identification of the age, comparative analysis of strata and determination of the spatial location of the fault points, the author determines the latest active age of the 7 faults and which faults are still active.(2) Construct the 3D surface model of active faults. Based on the multi-source exploration data, the composition and space-time characteristics of active faults and the relationship between them, this paper builds a spatial data model for the 3D surface model.Then it builds various geological interface of the active fault model based on spatial data model and GOCAD modeling platform, and amends them several times according to the characteristics of the active faults and the thinking of iterative modeling and incremental refinement. On this basis, by the order of the age of the geological bodies from new to old and the complexity of it from easy to difficult, the fault planes, stratum surface are combined with other geological interfaces to form the surface model of each geological body.(3) Construct the 3D solid model of active faults. The surface model is transformed into solid model by using cubes with side length of 50m to fill surface model and attaching attribute values for them. With the logical calculation function of each geological body model, the entire 3D solid model of active faults in the study area is constructed by subtraction and reverse selection.