9528517 Anderson The primary goal of this project is to predict the strong ground motions which will result from future earthquakes, with sufficient precision to be reliable for engineering applications; and equally important, to develop a system in which this capability will be readily available to anyone. Data from the US- Mexico strong motion array in Guerrero, Mexico provides one important means to calibrate the method, since it covers a large range of magnitudes and distances with stations on rock. Calibrations are also made with other data from throughout the world. The first year addresses the system for stations on rock; the second year concentrates on predictions for stations on sediments, including nonlinear effects; while the third year focuses on implementing 2D and 3D basin effects into the predictions. The aim is to make the system very easy for the user. Predicted strong motions are to be in the form of very realistic synthetic seismograms. The seismogram provides a link between the seismologist and the engineer; the numerous parameters that describe aspects of strong earthquake ground motions are all derived from accelerograms. A goal of this project is to work toward the time when regression analysis will be replaced by the generation of suites of synthetic accelerograms that are appropriate for the magnitude, distance, region, and site of interest, and which are closely calibrated by observations. These suites of accelerograms are used to obtain the mean and the variability of the desired ground motion parameter for the application of interest. This process will be made easily available to anyone with Internet access to the World Wide Web (WWW). The WWW page will be set up so that anyone accessing it can generate synthetic accelerograms. The user will be guided through a set of questions which will specify the necessary input, generate one or many seismograms, and retrieve the complete time series or commonly used parameters (such as peak acceleration or spectral amplitude) specified. Some state-of-the-art projects on seismic hazard are already using synthetic seismograms. These same techniques will be available to any design project, leading to improved earthquake- resistant designs at all levels. ***
