Southern California Earthquake Center Strong Motion Borehole Sites
Under the Southern California Earthquake Center, a borehole instrumentation program has been funded to increase the number of borehole strong motion recording stations in southern California. Through collaboration with many agencies involved in the California Integrated Seismic Network (CISN), including the USGS Pasadena, the USGS NSMP program, the CGS CSMIP program, and Caltech, the SCEC borehole instrumentation program was able to get 12 strong motion sensors installed in boreholes throughout the Southern California region. All the data from these stations is sent in real-time to Caltech and the CISN, and archived in the Southern California Earthquake Data Center (SCEDC). The majority of these sites are single downhole and surface pairs of strong motion sensor, typically associated with historical strong motion sites that have recorded significant events previously. The SCEC borehole instrumentation initiative also had significant collaboration with the ROSRINE program. This collaboration meant that the strong motion sites also have geotechnical site characterization data associated with the instrumented boreholes.
While the SCEC borehole sites are not extensive arrays like the previously mentioned arrays, they still represent a significant resource for understanding strong ground motions and the effects of surface geology in future events recorded at these sites. Figure 14 shows a map of borehole stations in Southern California region. This figure also includes the locations of borehole stations in the region operated with resources other than SCEC. More details of the SCEC stations will be provided in a report to the second Geotechnical Strong Motion Array workshop.
Figure 14. Southern California Borehole Instrumentation.
