The SCEC Phase III Strong-Motion Database

Jamison H. Steidl, & Yajie Lee

Published December 2000, SCEC Contribution #513

As part of the Southern California Earthquake Center (SCEC) Phase III effort to include site effects in hazard models for southern California, a regional database of strong-motion observations was developed. The observations consist of the peak ground acceleration (PGA) and 5% damped response spectral accelerations (RSA) at 0.3, 1.0-, and 3.0-second period from 28 earthquakes and 282 stations. A total of 449 pairs of horizontal PGA and RSA observations that were taken from the SCEC Strong Motion Database (SMDB) are presented here. The phase III database includes earthquakes with moment magnitudes larger than 5.0 and stations in southern California, with locations between 32° and 36° North latitude. Observations from buildings with more than two stories, and dam abutments or crests are excluded from the database. Observations with distances of 150 km or greater were also excluded. The agencies that provided the data to SMDB are the U.S. Geological Survey, California Strong Motion Instrumentation Program, University of Southern California, and the Los Angeles Department of Water and Power. The database also contains site classification information for each station. A first general classification is based on the 1:750,000 California map of Quaternary, Tertiary, and Mesozoic geologic units. A second more detailed classification is based on Quaternary mapping in the Los Angeles region. A third classification is based on the correlation of surface geology with shear-wave velocity in the upper 30 meters. A depth-to-basement parameter is assigned to stations that are located within the boundary of the SCEC 3-D velocity model. Special parameters associated with particular attenuation relations, such as different distance measures, a hanging wall flag, and fault type flag are also assigned to each observation. These data are all presented within the tables and figures of this paper, and also have been made available via a downloadable file on the Internet (http://smdb.crustal.ucsb.edu/~phase3).

Citation
Steidl, J. H., & Lee, Y. (2000). The SCEC Phase III Strong-Motion Database. Bulletin of the Seismological Society of America, 90(6B), S113-S135. doi: 10.1785/0120000511.