Syvä-Suomi: Illuminating the Finnish lithosphere with geophysical arrays

The continental lithosphere preserves the record of tectonic evolution while hosting resources and structures of major scientific and societal importance. In Finland, lithosphere has been investi-gated through numerous geological and geophysical surveys, but differences in spatial coverage, acquisition and resolution limit their integration into a consistent national-scale representation. Global initiatives have shown that the modern way to image the lithosphere is systematic, at national or even continental scale, with uniform coverage and standardised acquisition, an approach that is more effective, more economical and more environmentally sustainable. Syvä-Suomi is Finland’s contribution to this movement, at unprecedented resolution, and the foundation of a digital twin of the Finnish lithosphere into which decades of legacy geophysical data and complementary geoscientific data and models can be integrated. The initiative is intended to be multiphysics, opening with a nationwide long-period magnetotelluric survey and designed to grow through further geophysical methods. Past, present and future observations can then be assimilated into a single representation of the subsurface, maintained and updated continually. A national model can support applications in resources, energy, infrastructure, geological waste disposal and geohazards, while advancing understanding of Fennoscandian tectonic evolution. The multidisciplinary scope of the initiative also makes it a training ground for the next generation of geoscientists, data scientists and AI researchers in Finland and beyond.