Site characterization, with the goal of measuring VS30, was performed at 27 strong motion stations across Central and Southern California. These stations, belonging to the National Strong Motion Program, spanned four counties and varied geophysical environments. Primarily employed were the Simplified Site Characterization Methods (SSCM) as an efficient yet robust method for measuring VS30. The active-source SSCM were designed for Rayleigh-wave MASW analysis, while the passive-source methods were designed with ESAC analysis in mind. Also employed along the El Centro Array were conventional large-array MASW and ambient microtremor techniques, and HVSR site characterization techniques.
