Marine controlled source electromagnetic experiments at potential CCS sites on basalt complexes of the Vøring Plateau offshore Norway

As part of the PERAS project, basaltic complexes relevant to potential CO₂ storage on the mid-Norwegian margin have been investigated. IODP Sites U1571A and U1572A sample two contrasting volcanic domains: based on seismic interpretations, site U1571A is located on a faulted lava-flow field, whereas site U1572A to the west is located on a younger pitted surface interpreted to reflect the interaction of lava with wet substrate during the original emplacement. These domains also differ in structural deformation, with abundant local NS–oriented normal faults in the eastern flow field, and comparatively minor faulting in the western pitted domain.

We present first results of controlled-source electromagnetic (CSEM) experiments acquired during cruise MSM140 (4.9–9.10.2025) across the Vøring Plateau, offshore Norway. To investigate how emplacement style and deformation influence basalt structure, two CSEM experiments were carried out covering the area around sites U1571A and U1572A. A third experiment was measured along a profile line connecting the two sites. In addition, two experiments were carried out around ODP Site 642E to provide a regional reference and to assess regional lateral homogeneity of the basaltic complex.

For measurements we used the towed transmitter system CAGEM, which allows for measurements with two horizontal transmitter polarizations. For each of the five experiments, 12 seafloor receivers nodes (OBEMs) were deployed onto the seafloor. This allowed us to collect data in both inline and broadside configurations, improving sensitivity to resistivity anisotropy and 3D structural variability.