A DesignSafe earthquake ground motion database for California and surrounding regions

This article presents a ground motion database for California and its close surroundings (i.e. areas near the border in Nevada, Oregon, and Arizona) from earthquakes between 1999 and 2021. This data set includes events with magnitudes larger than 3.2 and focal depths less than 40 km, and it is available on DesignSafe. Ground motion records and events included in this data set are collected from 65 different seismic networks and processed with an automated software tool called gmprocess, which was developed by the United States Geological Survey (USGS). Path measures such as rupture distance and epicentral distance are computed, 5%-damped spectral accelerations, duration metrics, and other ground motion intensity measures (IMs) are provided for records that pass the quality assurance check performed by the gmprocess toolkit. The quality of processed ground motions is also screened by using outlier detection algorithms and a multiple wave-train arrivals identification algorithm. In addition, site metadata are provided, including wave velocity information (from proxy-based time-averaged shear-wave velocity for the top 30 m, V-s30, and from P- and S-wave measured velocity profiles when available), predominant frequency measured from microtremor-based horizontal-to-vertical ratios (mHVSR), and site-specific (high-frequency spectral decay) kappa(0) values computed from multiple ground motions recorded at sites when available. The final database contains 287,804 three-component ground motions recorded at 3709 stations from 2641 earthquakes with magnitudes and distances ranging from 3.2 to 7.2 and 0.15 to 335 km, respectively. This ground motion database contributes to advancing both engineering seismology studies and earthquake engineering applications in shallow crustal tectonic settings.