A SEISMIC EXPERT SYSTEM

For many seismogenic regions of the world, regional seismic zonation maps do not exist or are constructed without the benefit of local information and lack the detail necessary to represent the complex system of faults in the region. Site-specific seismic hazard analyses and the determination of design seismic parameters for static and dynamic analyses of structures require the involvement of experts, and can be time-consuming and expensive. Curre,ely, the most recently developed techniques for ground motion analyses are not widely available to responsible agencies and other practitioners in the field. These techniques are also not designed to easily incorporate the most recent findings on the character of seismogenic sources, including data on fault segmentation, slip rates, and other paleoseismological details of the active faults in the region. A seismic expert system is being developed for deriving site-specific deterministic and probabilistic peak ground motions, response spectral values, and ground motion time histories using state-of-the-art techniques. The expert system will be designed to guide the less-trained user through the process of seismic hazard analysis. The system, however, will also allow more experienced users to conduct parametric analyses and research. The user will be able, upon specifying the location, velocity-depth profile, and material properties for the site, and the seismic risk levels, to obtain the peak ground motions based on both probabilistic and deterministic analyses, empirical response spectra, site-specific theoretical response spectra, and simulated ground motion time history. The system allows the user to select the method and the desired seismic and fault parameters to be used in the analysis. Given that the system is modular in form, updating the technical methods and database will be a manageable process