A GIS-Based System For Probability Evaluation Of Potential Surface Displacement On Active Fault Segments Associated With Earthquakes--Theory And Practice

At present, people mainly use deterministic methods for evaluation of potential surface displacement on active fault segments associated with earthquakes. On the base of active fault segmentation, we analyse the earthquake probability on a fault segment in a period of time (or a use period of constructions) and evaluate the maximal potential surface displacement. But this method has no difference in different significant constructions and in different relative positons of constructions on the active fault segments. All constructions are fortified in accordance with the maximal potential surface displacement. This results in conservative fortification and large investment against earthquakes.The third generation seismic division map (1990) gives the intensity under 10% exceeding probability in 50 years. The fourth generation seismic division map (2001) adopted the same exceeding probability. So we should adopt the similar method in evaluation of potential surface displacement of active fault segments.The aim of probability evaluation of potential surface displacement of active fault segments is to develop a method based on probability to evaluate the displacement fatalness in a period of time for engineering seismological application. On the basis of previous studies, this work provides a concise representation by words and correspondent mathmatical formula."Probability Evaluation of Potential Surface Displacement of Active Fault Segmnets Associated with Earthquakes" can be defined as follows:It is used to compute the exceeding probability of the construction points on a fault where possible displacement U is not less than construction bearable displacement d in a period of time t. The distance between the construction point and the charactristic earthquake center is s. It can be written asThe data size of evaluation of potential surface displacement is very large. Although common computer languages are available, the large data size cannot be managed and maintained effectively. On the other hand, there is no commericial GIS system that could provide exceeding probability models. So this function should be put in commericial GIS systems by their extending interfaces. The useful function of a fundamental GIS system lies in its data managing capability and interface extending capability. Considering the strong function of the ESRI GIS software in these two aspects, this work has designed and developed the evaluating system for potential surface displacement by the probablity method.The main results of this thesis can be summarized into two aspects. 1. It' s a pilot study on building the method and the flow for "probabilityevaluation of potential surface displacement on active fault segments" . In this flow framework, the distrbution of potential surface displacement along seismic active fault segments is obtained by using statistical data. It provides a method to predict characterastic earthquake epi centers. It can compute the contribution of characterastic earthquakes and possion earthquakes to exceeding probability. Finally it synthetizes both of them as an exceeding probability of potential surface displacement of active fault segments associated with earthquakes.Through the basic computation above, the following results can be acquired: (1)Any construction site' s exceeding probability on a fault segment or displacement value under some exceeding probability in a period of time.(2)with the same displacement value, any construction site' s exceeding probability or the location where exceeding probability reachs some value.2. Making use of CIS, large-scale spatial database (GeoDataBase) and the COM/DCOM technical standard, a N-tier network computing system based on TCP/IP protocal is built. This system views integrity and consistance of the spatial database as its keystone. It takes component service as its core; realizes an ArcGIS-based computing client. Although the function of the system is very simple and the scale of the GeoDataBase is very small, it includes some important techniques that belo...