Marine Geophysics

Marine geophysical surveys are widely used across coastal, nearshore, and inland waterway projects, including port and harbour developments, dredging programs, waterway crossings for horizontal directional drilling (HDD), pipelines and bridges, and coastal vulnerability studies. They are also used for pipeline and cable route surveys, transition zone investigation, and the detection of submerged objects and heritage features.

Yes. Methods such as sub-bottom profiling and seismic refraction are commonly used to map depth to rock and characterise subsurface conditions beneath rivers and seabeds. These techniques provide continuous profiles along alignments, improving confidence in ground conditions where intrusive investigation is limited.

The most appropriate method depends on the project objectives, site conditions, and required depth of investigation. In many cases, a combination of techniques, such as bathymetry, sub-bottom profiling, and seismic methods are used to provide a comprehensive understanding of seabed and subsurface conditions.

Accuracy depends on the method used, site conditions, and survey design. Bathymetric data can achieve high positional and vertical accuracy, while sub-bottom and seismic methods provide reliable estimates of subsurface layering and depth to rock. Results are typically interpreted alongside geotechnical data to improve overall confidence.

Key information includes site location, access constraints, water depths, tidal conditions, existing survey or geotechnical data, and project objectives. This allows appropriate selection of marine geophysical survey methods and efficient survey planning.

Survey duration depends on the size of the area, water depth, weather conditions, and scope of work. Nearshore and waterway surveys are often completed within a few days, while larger or more complex investigations may require longer, particularly where weather or access constraints affect operations.

Deliverables typically include processed geophysical datasets, interpreted sections, and georeferenced outputs such as bathymetric surfaces, sub-bottom profiles, and anomaly maps. Results are provided in standard GIS and CAD-compatible formats, along with a technical report outlining methodology, interpretation, and key findings.

Marine geophysical surveys provide continuous spatial coverage across a site, whereas drilling and sampling provide point-based information. In many projects, intrusive testing is typically undertaken on land, with marine geophysics used to extend coverage into nearshore and transition zone environments and tie subsurface conditions across the land–water interface.

Yes. Marine geophysical surveys can be designed for shallow water, rivers, and transition zone environments using appropriate equipment and vessel configurations. These areas often require flexible survey approaches due to access and environmental constraints.

Survey quality can be influenced by factors such as sea state, water depth, seabed conditions, and environmental noise. Careful survey design and real-time quality control are used to optimise data quality under varying conditions.

Marine geophysical surveys are generally designed to minimise environmental impact, with most methods producing low to moderate energy levels compared to large-scale offshore seismic surveys. The potential for disturbance depends on the survey method, equipment used, and local environmental conditions.

Where required, surveys can be planned and managed in accordance with environmental guidelines, including consideration of sensitive species, timing restrictions, and operational controls. A marine fauna observer can be engaged to monitor activity and minimise potential interaction between survey operations and marine fauna.