Land-seismic capabilities at GEUS

The Geological Survey of Denmark and Greenland (GEUS) has recently expanded and modernised its land seismic equipment portfolio to support high-resolution seismic imaging and monitoring for research, public-sector tasks, and industry collaboration. This contribution presents the current land seismic capabilities at GEUS, acquired during late 2023 and early 2024, and highlights their applicability across a broad range of near-surface and crustal-scale investigations.

The source capability is centred on two modern vibroseis trucks (INOVA UV2), providing peak forces of up to 115 kN and a broad operational frequency range from below 1 Hz to 400 Hz. The units comply with EU Stage V emission standards, enabling environmentally responsible seismic acquisition in both urban and rural settings. Their flexibility makes them suitable for applications ranging from high-resolution near-surface surveys to deeper structural imaging and monitoring.

On the receiver side, GEUS operates an extensive wireless nodal system comprising 1200 Sercel WING digital field units equipped with one-component MEMS accelerometers. The system offers high timing accuracy via GPS synchronisation, bandwidth up to 400 Hz, and long battery autonomy (up to 50 days), allowing efficient large-scale 2D and 3D deployments as well as long-term passive or active monitoring campaigns. Additional sensors can be leased to further upscale acquisition geometries when required.

For rapid, high-resolution profiling, GEUS also maintains a 200 m landstreamer system (SeisMove) equipped with 100 three-component MEMS sensors at 2 m spacing. With bandwidths up to 800 Hz and sub-millisecond sampling options, this system is particularly well-suited for urban surveys, infrastructure studies, and near-surface characterisation where speed and data quality are critical.

These nodal capabilities are complemented by two ASN OptoDAS C01-S Distributed Acoustic Sensing (DAS) interrogators, enabling the use of standard fibre-optic cables as dense, multi-kilometre seismic sensor arrays. The DAS systems significantly extend the receiver portfolio by allowing rapid deployment on existing dark fibers, ultra-dense spatial sampling, and continuous monitoring. They are particularly well-suited for infrastructure monitoring, near-surface studies, and emerging applications in geothermal energy and CO₂ storage surveillance. GEUS also possesses 4 km of its own armoured fiber-optic cable with 4 individual 9/125 μ single-mode OS1-grade fibers for local, high-signal-to-noise ratio deployments.

Together, these complementary systems position GEUS to deliver state-of-the-art land seismic imaging and monitoring solutions, supporting research in seismicity monitoring, groundwater, geohazards, infrastructure, geothermal energy, and CO₂ storage, as well as national and international collaborative projects.