The pan-European Engineering Strong Motion (ESM) flatfile: comparison with NGA-West2 database

In the first months of 2018, a parametric table (flatfile) related to the Engineering Strong Motion (ESM) database was released and disseminated through a website (http:// esm.mi.ingv.it/flatfile-2018). The flatfile contains intensity measures of engineering interest and associated metadata of three-components manually processed waveforms. The uniform collection of strong motion data and the compiling of quality-checked metadata allow the users among practitioners and seismologists, to test and calibrate Ground Motion Models (GMMs) for hazard assessment purposes or for the analysis of the seismic structural response. In 2013, a database used for similar purposes was constructed in the framework of the NGA-West2 project, whose main objective is to update and improve the Next Generation Attenuation (NGA) models for active tectonic regions, such as California. In this framework, a flatfile containing several parameters, such as peak parameters and ordinates of the pseudo-acceleration elastic response spectra, along with metadata of events and stations was released. The scope of this paper is to highlight the main differences between the two tables in terms of structure, data statistics and qualification of metadata.