Predicting Strong Ground Motions
Modern approaches to assessing facility performance rely on good information about likely ground shaking at the site. Many improvements have been made in providing this information in the past several decades. Access to earthquake ground motion data has been hampered, however, by difficult access to the large body of data as well as by the inconsistency in how the data are gathered and stored.
Recognizing the need to improve access to earthquake ground motion data, PEER embarked on an effort to create a web-based, searchable database of strong ground motion data. The first step was to gather the most important records from around the world. The next step was to ensure that all the data had been processed consistently and that it was reliable in all regards. The next step was to gather related information such as earthquake magnitude, distance, site conditions, and other relevant engineering parameters. Finally, PEER created the online database to make all the information available. In its completed form, the PEER Strong Motion Database brings together over 1,500 strong ground motion records from 143 different earthquakes in a web-accessible format.
The PEER Strong Ground Motion Database is serving a number of useful purposes. Two important examples are:
- - Practicing earthquake engineers need strong ground motion data to “shake” computer models of buildings, bridges, and other facilities. The PEER Strong Ground Motion database has proved to be very popular among engineers who increasingly are using it for design studies. The database is now cited as a primary source of ground motion records in the latest revision of the Building Seismic Safety Council’s NEHRP Recommended Provisions.
- - The database is also being used by researchers to develop improved attenuation relations — these tell an engineer how strong the shaking will be at a site as a function of earthquake magnitude, mechanism, distance, and site conditions. A major PEER project is bringing together the major developers of attenuation relations from around the U.S. to guide them, using the PEER database, to develop the next-generation of attenuation relations.