The CISN consists of several different types of seismic instrumentation, reflecting the significant changes in technology over the last 30 years as well as the multiple goals of seismic monitoring. The CISN uses different types of sensors (short-period, broadband, and strong-motion) in different environments (surface and/or free field, structures, boreholes) with different recording and communications systems.
The tables figures below illustrate the range and distribution of seismic instrumentation in California and western Nevada deployed by CISN partners and collaborators. These numbers and maps were put together by David Oppenheimer, of the USGS Menlo Park, as part of a planning meeting for future CISN instrumentation held in June 2002.
California and western Nevada by the numbers (as of June 2002):
Not all of these sites are recorded digitally and as shown in the table, a significant fraction of the strong-motion sites are without communications. These maps show the distribution of this instrumentation across the state. The GIF images provide a broad overview; the PDF provide more detail (but the files are quite large!).