Collection, Documentation and Dissemination of Strong Motion Data From Recent Large Earthquakes in Japan

点击翻译按钮获取中文摘要

9527929 Somerville The objectives of this project are to gather and provide access to digital strong motion recordings from recent large Japanese earthquakes; to document the source, path and site parameters required for the interpretation and use of the data; to compare them with attenuation relations used in the United States; and provide commentary on their relevance to ground motions in the United States. The aim is to provide basic data for use by the earthquake engineering research community. In the two year period between January 15, 1993 and January 17, 1995, five major earthquakes occurred and were widely recorded in Japan. The smallest of these earthquakes, the magnitude 6.9 Kobe earthquake of January 17, 1995, was the most damaging because of its occurrence in a dense urban region. The four other earthquakes, with magnitudes in the range of 7.5 to 8. 1, occurred in subduction zones, and were all larger than any earthquake in the United States for which we have strong motion recordings. These strong motion data are difficult to acquire, and most investigators in the United States do not know how to acquire them. Further, the data cannot be directly used in the development of empirical ground motion models because different magnitude scales are used in Japan as compared to the USA (JMA magnitude instead of moment magnitude); and epicentral distance is used in Japan instead of the closest distance to the fault. These conditions result in the underutilization of these potentially valuable strong motion data. The project involves the following: 1. Gather digital strong motion time histories together with the many categories of information that are required for the interpretation and use of the time histories. These include source parameters such as seismic moment, focal mechanism and tectonic category; path parameters describing the closest distance to the recording site; and available geotechnical data from the recording sites. 2. Using these data, c ompare the Japanese ground motions with corresponding empirical attenuation relations used in the United States. 3. Based on this comparison, prepare a commentary on the records describing their appropriateness for particular seismic source regions in the United States. The digital time histories, parameter information, comparisons, and commentary will be archived on the Internet and provided to the National Geophysical Data Center in Boulder, Colorado. The proposed work will implement all of the major recommendations of the 1993 International Workshop on Strong Motion Data concerning the dissemination of strong motion data from recent earthquakes in Japan. ***