Abstract
<jats:p>Abstract. Controlled Source Seismic (CSS) data are key to understanding the structure and composition of the lithosphere at different scales. They are highly valuable both in their own right and as input to multidisciplinary studies and Earth system modelling. The challenge for scientists is to find existing data, assess their relevance for a particular purpose, and eventually get access and permission to reuse selected data sets. The European research infrastructure for solid Earth sciences, EPOS (European Plate Observing System) was designed to solve such problems. It is a multidisciplinary, distributed research infrastructure that facilitates the integrated use of data, data products, and facilities from the solid Earth science community. FAIR principles are put into practice, enabling access to data and products from hundreds of scientific data services across Europe. A community building effort for Controlled Source Seismic data was started at the EGU24 and SEISMIX2024 conferences, with the aim of developing a metadata model for data set discovery, as no existing standards or common practices for describing CSS data sets could be identified. This objective was achieved by early 2026 and the results are presented in this paper, together with a data service as an interface to the EPOS Platform. The metadata model is sufficiently detailed to allow a scientist to decide whether a discovered data set is fit for the intended reuse purpose or not. On the other hand, obligatory attributes are limited to avoid incompatibility with the diverse metadata models of potential data providers. The EPOS CSS metadata catalogue will meet FAIR and Open Data principles. The data sets registered in the metadata catalogue should ideally also be FAIR and Open. However, enforcing such a policy would exclude a large part of the existing seismic data. Therefore, the metadata model was designed to also describe closed data by providing suitable information on the legal constraints. In this way, the CSS metadata catalogue will be most useful to the scientists by providing the largest coverage while also advertising FAIR data and Open Science to the data providers.</jats:p>