Figure 1C. Seismograph stations in the Willamette Valley area operated by or recorded at the PNSN at the end of September, 2002. Black crosses indicate the locations of short-period vertical seismometers, while red triangular symbols represent the locations of three-component broad-band seismometer installations. White squares denote the locations of three-component strong-motion seismometer stations, and cities are designated by unfilled diamonds.