Ground-motion flatfiles are commonly used to develop ground motion models (GMMs) and for systematical analysis of ground motions over a wide range of distances and earthquake magnitudes. A flatfile is organized as a table of properties and various intensity measures of earthquake waveforms, including data processing parameters. Here we present a comprehensive processed ground-motion flatfile containing data from the Kyoshin (K-NET) and Kiban-Kyoshin (KiK-net) networks operated by National Research Institute for Earth Science and Disaster Resilience (NIED) (2019) in Japan (Okada et al., 2004; Aoi et al., 2011). This flatfile contains 914,628 ground motions from 18,018 events recorded by 1,749 stations. Out of these, 434,898 ground-motions are from KiK-net and 479,730 from K-net. The events were recorded between June 1996 and September 2024, covering distances up to 1200 km and magnitudes between 2.5 and 9. The ground motions have been automatically processed, and metadata describing each event and record are provided in the flat file.
An overview of the flatfiles and the processing steps to derive the reported ground-motion parameters is provided in this report. Further details and discussion about the flatfile compilation can be found in the corresponding publication: Loviknes, K., von Specht, S., Lilienkamp, H., Händel, A., and Cotton, F. (2025). Harmonized KiK-net and K-NET flatfile for systematic analysis of earthquake ground motions (submitted to Seismica, February 2025).
Ground motion models (GMM) have been employed in several domains, from traditional seismic hazard and risk analysis to more recent shakemaps and rapid loss assessment. In this framework, eGSIM is a Python package and web application intended to help engineers and seismologist in understanding how different models compare for specific earthquake scenarios and how well they fit to observed ground motion data, producing results as visual plot or tabular data in standard, accessible and convenient formats (CSV, HDF, JSON and several image formats).
Based on OpenQuake, a popular open-source Python library for seismic hazard and risk analysis, eGSIM incorporates and makes available in two user-friendly interfaces hundreds of published GMMs implemented and tested in OpenQuake: an online graphical user interface (GUI) accessible at https://egsim.gfz-potsdam.de, ideal for comparisons that can be visualized or downloaded as images, and a web application programming interface (web API), implemented along the lines of popular seismological web services (FDSN), more suited for comparisons that may be automatized in scheduled jobs, or need to be integrated into custom code and further processed in the user's own workflows.
By incorporating databases in form of so-called flatfiles (ESM) and regionalizations derived from seismic hazard models (SHARE, ESHM20), eGSIM allows users to seamlessly select data for comparison and models for comparison based on regions of interest. It also features management scripts to smoothly incorporate new flatfiles or regionalizations from future research projects.Moreover, via the generation of flatfile templates based on a custom selection of GMMs, and the possibility to upload user-defined flatfiles, eGSIM facilitates the non-trivial task of compiling data for model comparison, and can be used to analyze ground motions from any data set recorded anywhere in the world, including rapid analysis of earthquake records following large events.