Application To Pulse The Urban Underground Three-dimensional Velocity Structure Of The Modeling Study

Three-dimensional underground velocity structural modeling is very significant both in geology and ground quake digital simulation, and the data is also the base of region earthquake research. According to the new achievement of the research on the microtremors inland and broad, we can obtain the underground structure by using the method of spectrum ratio of horizontal to vertical microtremors (H/V ratios). The method is used to analysis the microtremors signal. This thesis will use the achievement, and then base on the building of the Ningbo Basin's underground velocity structure, and then observe the microtremors of Ningbo district and compute each observed point. The basic period of the HV spectrum can be obtained. Synthetically using the wave velocity reconnaissance we can obtain the parameter of each physical layer, and then we can presume the depth of each underground layer of the observed point. At last, we can obtain a three-dimension underground structure model according to the microtremors observation. At the same time, through using the geological and the geographical data of each layer in Ningbo district and combining the data from the microtremors observation, we can finally build the three-dimension underground structure model.In the interest of demonstrating the feasibility of building the underground structure using the data of microtremors, the thesis will at last use the microtremors inversion method to check it. That is, through the selection of several points and the compare the HV spectrum of the computation result and the observation result. We can demonstrate the feasibility of the method according to the consistency of the two spectrums. Putting together, the research content of the thesis will include the two points:1. The research on the feasibility of the three-dimension underground structure model building using microtremor data.2. The practice of building the three-dimension underground structure model of Ningbo city using microtremor data.3. Summarise the method of building the three-dimension underground structure model...