A colorful 30" x 36" wall poster (USGS Open-File Report 01-164) showing earthquake ground-motion amplification in Southern California is now available for $10. The wall poster is a joint publication of the Southern California Earthquake Center (SCEC) and the USGS.

The two most important factors influencing the level of earthquake ground motion at a site are the magnitude and distance of the earthquake. This map shows the influence of a third important factor, the site effect, where conditions at a particular location can increase (amplify) or decrease the level of shaking that is otherwise expected for a given magnitude and distance. Site effects at the areas shown in yellow will amplify ground motion by a factor of five, on average, relative to those shown in blue. Combining this information with estimates of where and when earthquakes are likely to occur should provide improved assessments of seismic hazard.

The map is based on information in the SCEC Phase III Report, a collection of 14 papers published in a special issue of the Bulletin of the Seismological Society of America (2000, Volume 90, Number 6B). The image is intended to be an illustrative representation of some of the findings contained in the report. It is not intended for seismic-hazard analysis or engineering design; those interested in applicable resources should refer to the original report and to the SCEC Phase III web site (http://www.scec.org/phase3).

To order the wall map, request an order form by calling 213-740-3262 or e-mailing scec@usc.edu (be sure to include your address or fax number in your message).

Download the poster (PDF and .eps versions)