Epos-France Database of Earthquake Ground Motion for Mainland France: 1996–2021 Updated Version

Abstract For ground-motion analyses, seismic hazard assessment and earthquake engineering applications, high-quality data sets of earthquakes recordings over a wide frequency range (ideally 0.1–100 Hz to cover the frequency band of interest for engineering applications) are needed. Although in the past the implementation of such ground-motion data sets was mostly concerning active seismic regions, in recent years, interest for it has also grown in low-to-moderate seismicity areas, where epistemic uncertainties associated with seismic hazard estimates were largest, due to lack of data. In this article, we provide an updated version of the Traversa et al. (2020) ground-motion data set for mainland France, now extended from 1996 to 2021. This updated data set contains more than 16,000 high-quality waveforms recorded by 622 accelerometers and broadband seismometers of the Epos-France network (formerly RESIF: Réseau Sismologique et Géodésique Français), related to more than 600 earthquakes (ML≅2−5.6) that occurred in France and neighboring countries. The updating procedure includes (1) efficient download and basic processing (instrument-response correction, baseline correction) of the available waveforms, using the stream2segment package (Zaccarelli et al., 2019); (2) mixed manual and automated waveform inspection and phase-arrival picking stage, based on the Stockwell transform (Stockwell et al., 1996); (3) waveform processing leading to the main ground-motion parameters computation; (4) verification and validation procedure implemented by Traversa et al. (2020), based on residual analyses. All these steps are applied to the entire data set, including the content of the previous version, resulting in a completely homogeneous data set. The updating procedure, the main features, and the characteristics of the updated Epos-France data set are discussed in this article, and the data and metadata are distributed through associated flatfiles and ASCII files.