The UK Centre for Seabed Mapping (UK CSM), a group of over 30 public sector organisations with a shared commitment to collect and share high-quality marine data, will undertake a seabed mapping survey – CSM2026 – to explore and map the seabed along the UK south-west coastline.

Throughout the four-week survey, using cutting‑edge survey technology deployed from the Research Vessel Cefas Endeavour, a team of 26 scientists from across the field of maritime research will collect vital hydrographic, geological and environmental data when they set sail from Lowestoft next week.

51ÁÔÆæ marine geoscientists Dayton Dove and Duncan Stevens will be on board, with a primary focus on acquiring sub-bottom profiler (SBP) data. An SBP is a type of sonar system, emitting sound waves that both reflect off, and penetrate through, the seabed to image the shallow subsurface. Those that penetrate through seabed reflect off the geological layers and buried structures, providing 2D cross-sectional images of the subsurface. This data (and resulting subsurface maps) are required for many offshore infrastructure applications, and importantly also provide further information on the nature, composition, and stability of the seabed itself.

Convening multiple government agencies, the survey represents an unprecedented level of collaboration within the maritime sector. By combining their skills and capabilities in a single survey, the team aim to secure data to deliver the UK government commitments and make advances in how our seabed is mapped, understood and managed.

51ÁÔÆæ are one of eleven UK CSM member organisations, which also includes: the Maritime and Coastguard Agency (MCA); the UK Hydrographic Office (UKHO); Centre for Environment, Fisheries and Aquaculture Science (Cefas); Department for Environment, Food & Rural Affairs (Defra), The Crown Estate; Historic England; Joint Nature Conservation Committee (JNCC); Agri-Food and Biosciences Institute, Northern Ireland (AFBI); Natural England and the Royal Navy.

Over the course of the survey, the scientists on board will have the opportunity to work with experts from other public sector organisations, share skills, and source key seabed mapping data that supports a wide range of applications including offshore energy and infrastructure, marine ecosystem science, safety at sea, marine policy, and defence. The four-week research survey is due to take place between 20 April and 19 May. This will consist of two survey legs, starting in Lowestoft, Suffolk and ending in Falmouth, Cornwall. All organisations are supporting the planning of alternative sites to maximise the opportunity.

“This is the first time that such a large-scale, multi-agency, collaborative survey has been undertaken in the UK and it a really exciting venture. We are fortunate to have expert scientists and surveyors from across government who will collect a wide range of highly valuable data. The partnership approach provides opportunities to share knowledge and expertise, as well as providing invaluable training and offshore fieldwork experience.

“The alliance of organisations is working together to increase efficiencies for data collection, processing and analysis under the gather once, use many times philosophy.

“Seabed mapping data provides the UK with a foundational basemap of its marine estate. Such valuable datasets are increasingly underpinning the maritime economy and energy security, enabling sustainable management of marine resources, development of marine policies and planning, and improves our understanding of the marine environment.�

Andrew Colenutt, Chair of the CSM2026 Project Team and Head of Hydrography and Meteorology at the MCA

“The UK CSM has proven to be an excellent forum for marine surveyors, scientists, and managers from across the UK public sector, increasing awareness, collaboration, and visibility of a disparate range of seabed mapping activities and applications.

This survey is an excellent opportunity for drawing the diverse expertise from across the UKCSM, and of particular significance for geoscientists, will include the collection of sub-bottom profiler (SBP) data. BGS has advocated for acquiring SBP data on hydrographic surveyors in order to provide crucial sub-surface data for a range of applications.

Scientists and decision-makers working in the offshore environment are reliant on high-quality seabed data to inform the siting, design, and installation of offshore infrastructure projects, such as Offshore Wind installations, habitat and ecosystem mapping, archaeology, marine aggregates, coastal erosion and management, and baseline geological and environmental science.”

Dayton Dove, BGS Marine Geoscientist

“This joint survey is a fantastic example of what public sector collaboration can achieve when expertise, capability and purpose are aligned. By bringing together organisations from across the UK maritime sector through the UK Centre for Seabed Mapping (UK CSM), we are not only improving how the seabed is mapped, but deepening our collective understanding of the ocean environment, while also providing an opportunity for various experts to learn from one another.

“High‑quality seabed mapping underpins everything from safety at sea and environmental protection to sustainable development and supporting national security. Working together through the UK CSM allows us to maximise the value of data, share knowledge, and deliver insights that no single organisation could achieve alone”

Rear Admiral Angus Essenhigh OBE, UK National Hydrographer & Director of Data Acquisition at the UKHO and chair of the UK CSM Steering Committee

About the UK Centre for Seabed Mapping (UK CSM)

The , administered by the UKHO, was established in 2022 and coordinates the collection, management and access of seabed mapping data. Through collaboration, the UK CSM aims to improve understanding of the UK maritime estate and inform the effective management of marine resources. There are currently over 30 public sector organisations who are members of the UK CSM with an interest in marine geospatial information and data.

The 51ÁÔÆæ (BGS) has released a new shallow subsurface geological synthesis of the southern North Sea in the first formal review of this region since the 1990s. A wealth of new subsurface data has been generated through the rapid expansion of offshore wind farm (OWF) development since the last assessment.

In total, the new synthesis draws on data from 22 OWFs and cable landfall sites from recent publications and open data available through The Crown Estate . Bringing these diverse datasets together presented a rare opportunity to enhance our geological understanding of the region, providing a detailed baseline resource to support more efficient and better-informed offshore development projects in the future.

Findings from the updated review have revealed much greater geological complexity within the region than indicated by the previous assessment, which was developed between the 1970s and 1990s on the back of data collected during oil and gas developments. Modern OWF investigations, supported by comprehensive borehole drilling, cone penetration tests and seismic datasets, show that many of the geological formations contain a variety of distinct sedimentary characteristics. This complexity has direct implications for foundation design and ground modelling, including the identification of geo-engineering constraints and geohazards, which is crucial information for a wide range of offshore infrastructure development.

The assessment examined evidence across pre-glacial, glacial, interglacial and post‑glacial periods from 200 million years ago to the present day. Understanding how different sedimentary units were deposited provides vital insight into geological formations that may present specific geo-engineering complications. This includes mixed soils, boulders, glacially compacted sediments or organic-rich layers. Organic units can be problematic for cable installation due to their fibrous nature, presenting considerable challenges to cable routing.

It is not a requirement for UK offshore infrastructure projects to collect samples for dating and biostratigraphy; however, where they are available, absolute dating (radiocarbon and optical stimulated luminescence data) information has also been included within the assessment. Neighbouring countries such as the Netherlands recognise the value of this data, as it can help to better predict age-based sedimentary characteristics and ultimately better inform geotechnical characterisation around a project design.

The report outlines several recommendations to enhance the resource further, including improving fine-scale mapping, ingesting geotechnical datasets for each geological subunit and strengthening international collaboration to harmonise North Sea stratigraphy. The findings presented in the main report can be aligned with results presented in the , which is a data catalogue highlighting the key geological features and associated engineering constraints for OWF development as part of the . Both resources provide complementary datasets and criteria essential for evaluating OWF site suitability.

This work provides:

• an opportunity to advance scientific understanding
• resources to strengthen national collaboration
• supporting baseline evidence for the energy transition, energy security and wider marine planning
  

The release of this report marks an important milestone in compiling geological observations from literature and offshore wind farm development over the past 30 years or so. It brings together a wealth of new offshore geological data that enhances our understanding of the shallow subsurface in the marine environment in the southern North Sea. We hope this dataset will provide strong baseline evidence to support national and international collaboration for efficient offshore development and act as a blueprint for other areas around the UK Continental Shelf.

Nikki Dakin, BGS Senior Marine Geoscientist

We would encourage similar consolidation of geological information across the wider North Sea, Celtic Sea, Irish Sea, The Solent and English Channel, making full use of the substantial dataset holdings within the Marine Data Exchange. There is also significant potential to extend this approach internationally, working with neighbouring countries.

Such data provides a robust evidence base for industry, regulators and researchers, marking an important step toward a fully modernised geological model and improving our understanding of offshore stratigraphy across the UK Continental Shelf.

The report and geological assessment are now available online: .

51ÁÔÆæ would like to acknowledge The Crown Estate as well as wind farm developers for contributing reports and data to The Crown Estate Marine Data Exchange.

51ÁÔÆæ has developed a new, national-scale, offshore dataset that shows the distribution of previously interpreted Quaternary rock layers in the shallow subsurface of the UK continental shelf.

The BGS Offshore Quaternary 250K datasetcomprises a compilation of legacy BGS 1:250000 Quaternary geology map sheets, which were first published in the late 1980s to early 1990s. Large areas of the UK offshore are covered at a scale of 1:250000 and this is the first time these map sheets have been digitised and merged together.

The dataset is made up of vector polygons, each representing an area where a particular formation has been mapped. The legacy map sheet interpretations have not been modified during the digitisation; they are presented in their original form and have been ‘mosaiced’ together as a single digital product.

The dataset will help users, particularly those in the offshore renewables sector, to understand the stratigraphy that was mapped historically in a particular area and can be used for reference when completing site investigations.

The principal drive behind this release is to make original 1:250000 map data available in a digital format. Although work to refine Quaternary stratigraphical frameworks is ongoing, the map compilation is not informed by new data or analyses.

The Offshore Quaternary 250K dataset is the first time that these legacy offshore map sheets will be digitised, making it easier for users to access the data than ever before.

Andrew Dyson, marine geoscientist at BGS.

Renewable energy infrastructure, whether on- or offshore, requires in-depth understanding and accurate characterisation of the underlying geology.  Developers increasingly need detailed geospatial observations of the seabed and shallow subsurface, which are critical to the siting and design of offshore infrastructure such as submarine cables and offshore wind turbines. This is certainly true in the Bristol Channel, which is home to the second largest tidal range in the world. This high-energy environment has attracted much interest around the use of the seabed for tidal power and the potential to produce electricity from wave energy.

To support policy- and decision makers in this region, BGS has released an enhanced seabed geology map of the Bristol Channel, almost four times the size of the original, which extends from Carmarthen Bay to Newport and further south to the coast of Somerset.

Beyond offshore infrastructure, these maps also directly contribute to understanding of marine ecosystems, coastal management and defence activities. The data provides crucial information to those ensuring the port facilities along this coastline meet the requirements for these development opportunities.

As the UK transition to renewable energy gathers pace, these maps will become increasingly valuable to industry and stakeholders with an interest in developing clean energy, from offshore wind to tidal streaming, and in carbon capture and storage.

The successful implementation of offshore renewable energy projects and technologies and the development of ports in South Wales require a detailed understanding of the seabed. This new, expanded, fine-scale seabed map of the Bristol Channel will be an invaluable resource for developers, providing access to high-quality, detailed observations of the seabed geology that is vital to these kinds of developments.

Beyond its critical role in supporting the renewables sector, the map will also be useful to other data users, such as those involved with supporting marine ecosystems, coastal management and defence activities. It will also provide evidence for policy- and decision makers in the region.

Rhian Kendall, BGS Chief Geologist for Wales.

The map, featuring combined bedrock, sediment, bedrock structure and seabed geomorphology data, is available from BGS under the fine-scale maps section of theand is designed to be viewed at 1:10000 scale, or online as downloadable shapefiles. For information on licensing the downloadable GIS data (ESRI format), please contact digitaldata@bgs.ac.uk.

Seventy-four days offshore, 718 cores and 871.83 m of total core from three locations: this is the successful outcome after the end of offshore operations of IODP³-NSF Expedition 501: New England Shelf hydrogeology. The goal of the expedition was to take samples not only of sediment cores, but also of the water stored in both sandy aquifers and clayey aquitards beneath the ocean floor. Their existence has been known for decades but they remained virtually unexplored — until now.

The expedition is a joint collaboration between the International Ocean Drilling Programme (IODP³) and the US National Science Foundation (NSF), with the expedition being managed and technically supported by the team at BGS.

We set out with lofty goals of understanding the origin and age of this offshore freshened groundwater system through sampling of sediment and water in a difficult drilling environment consisting of sand and mud. With great teamwork between the science team, the technical staff and the drilling crew, we managed to get great samples, including via multiple groundwater pumping tests.

Those tests were a critical to the expedition and a first for scientific ocean drilling. And we did it! Now we have the samples for the science team to really dive into the data and understand the system, which will be helpful for understanding other offshore freshened groundwater systems around the world.

Prof Brandon Dugan, expedition co-chief scientist.

The pump tests were challenging and required us to adapt our processes to get the best possible samples of the groundwater. In the end we pumped nearly 50 000 litres of water from nine distinct places, in terms of location and depth below the sea floor.

This is a huge success story for something so novel. For me in particular, as a geochemist and not a hydrogeologist, I am so appreciative to everyone that leant their expertise. The team of hydrogeologists from the 51ÁÔÆæ especially was outstanding.

Rebecca Robinson, expedition co-chief scientist.

During the expedition, the science team rotated on and off the Liftboat Robert, transported by helicopter or supply vessel. The entire science team will meet for the onshore operations at the Bremen Core Repository, at the Center for Marine Environmental Sciences at the University of Bremen (MARUM), in January and February 2026 to split, sample and analyse the sediment cores and water collected. The cores will be archived and made accessible for further scientific research for the scientific community after a one-year moratorium period. All the expedition data will eventually be open access in the IODP³ MSP data portal in PANGAEA and resulting outcomes will be published.

I’m absolutely delighted for our BGS colleagues and the whole expedition team, who have delivered this outstanding and unique project for IODP³. The sediment cores, water samples and logging data they helped collect will now be analysed by the international science team to better understand the New England continental shelf and its freshened groundwater system, and I expect some groundbreaking results will emerge in the months and years ahead.

David McInroy, BGS project lead.

International approach

51ÁÔÆæ scientists are part of a science team with over 40 members from 13 nations (Australia, China, France, Germany, India, Italy, Japan, the Netherlands, Portugal, Sweden, Switzerland, the UK and the USA) that takes part in the expedition. The expedition itself consists of two phases: offshore and onshore operations. Offshore operations took place between May and early August 2025.

The expedition is conducted by the European Consortium for Ocean Research Drilling (ECORD) as part of the International Ocean Drilling Programme (IODP³), funded by IODP³ and the US National Science Foundation (NSF).

More information

Enhanced mapping of the UK Exclusive Economic Zone (EEZ) is being made available to the public for the first time, providing greater insight into the occurrence of earthquake hazard across an area of seabed that the country holds exclusive rights to, including those for energy production.

The updated modelling from BGS comes at a time when the UK is seeking to bolster its offshore renewable energy infrastructure and meet its net zero commitments.

These maps are the first new UK offshore seismic hazard maps for more than 20 years. Methodological and computational advances mean that we are able to better understand which areas hold the potential to be heavily impacted by seismic activity and how to model the uncertainty (what is still unknown or uncertain).

Offshore critical infrastructure, including windfarms and carbon capture and storage, are both essential for the transition to net zero, but it is also vital that we know what the hazard is so that high consequence structures can be designed appropriately to reduce risks to people and the environment.

Dr Ilaria Mosca, earthquake hazard researcher, BGS.

Earthquakes in the UK

The UK experiences between 200 to 300 earthquakes annually, with the largest earthquake ever recorded being a 6.1 magnitude earthquake that occurred in 1931 in the Dogger Bank area of the North Sea, about 100 km from the east coast of England. More recently, in 2022, a 5.2 magnitude earthquake in the northern part of the North Sea shut down operations at an offshore oil platform without causing significant damage.

The North Sea and the Irish Sea have a strategic role in supporting the UK decarbonisation and net zero carbon ambitions due to the increasing number of licensed carbon capture and storage (CCS) sites located there. The presence of historic seismicity near these offshore CCS sites emphasises the importance of robust estimates of the potential earthquake hazard to underpin the planning and design of this critical offshore infrastructure.

The seismic hazard maps

The seismic hazard shown in the maps is computed using a model that consists of two parts: one that characterises earthquake occurrence (where they occur and their frequency of occurrence) and another that describes the ground shaking that may result from potential future earthquakes. The model is based on historical and instrumental observations of earthquakes and their effects, and information and data relating to the tectonics and geology of the region under investigation.

These maps empower developers with the knowledge of the areas that have the greatest potential for key infrastructure, including CCS, to be built without the serious risk of damage caused by the ground shaking produced by future potential earthquakes, helping to ensure net zero can be achieved alongside the safety of those on and offshore.

Dr Ilaria Mosca.

Project partners and funding

The project was funded by the (IDRIC). The project partner was , an independent developer of low-carbon solutions for industrial emissions, including CO₂ storage and hydrogen. Storegga projects include the Acorn CCS, Cromarty and Speyside hydrogen projects in the UK, Trudvang CCS in Norway and Harvest Bend CCS in Louisiana.

More information

The products of this project are accessible through a .

In an effort to streamline petroleum licence information management, data from the National Hydrocarbons Data Archive (NHDA) has been transferred from BGS to the National Data Repository (NDR), which is hosted by the North Sea Transition Authority (NSTA). 

The NHDA was a system managed by BGS on behalf of the former Department of Trade and Industry and Department of Energy and Climate. It held geoscientific data from operators requesting relief from their data management and storage obligations. These Government departments and systems have been superseded by NSTA, which has created the NDR to make its data assets openly available to . The transfer of this data ensures users can freely access all data relating to petroleum licences in one place.

The data includes offshore surveys, well data and some seismic survey information, all of which are now freely accessible to download. The data could support a range of purposes, from use cases in traditional exploration and production to applications in the energy transition such as carbon storage and offshore wind.

The NSTA and BGS collaboration has enabled the formulation of plans for NHDA’s decommissioning after nearly two decades of operation.

This initiative reflects both organisations’ ongoing commitment to improving access to data to enable the UK energy transition, while maintaining energy security.

Nic Granger, NSTA Director of Corporate.

By working collaboratively with NSTA, we have enhanced access to this nationally important data archive to support the UK energy transition.

Emma Bee, head of the National Geoscience Data Centre.

For the first time in 25 years, new geological data has been used to create an offshore East Anglia fine-scale (1:10 000) map. The map captures essential insights that will prove invaluable in the pursuit of further renewable energy development in the area, whilst allowing for better protection of nationally important habitats and species. The map, released by BGS, reveals hidden geological features of the seabed offshore north-east Norfolk. It provides new insights into the longer-term geological evolution of the region, including the extent and legacy of glaciation that affected the area during the geological past.

Results of the research include:

• the first high-resolution geological map of the offshore area around north-east Norfolk
• mapping of a prominent area of an offshore chalk (bedrock) reef, a rare ecological habitat that has been designated a

• geology is dominated by superficial (Pleistocene) deposits and landforms that record the eastwards growth of a large delta followed by several phases of glaciation

The map has been created by the interpretation of high-resolution bathymetric data captured by the Maritime and Coastguard Agency, shallow seismic data and historical sediment samples.

The opportunities presented by this enhanced understanding of a vital part of the UK offshore environment are considerable, providing the tools to support a diverse range of offshore activities and applications, including scientific research, offshore development, conservation efforts and marine management.

It is particularly interesting that we have mapped an extensive area of offshore chalk reef that corresponds to a designated Marine Conservation Zone. The mapping has also identified widespread geological and geomorphological evidence for the longer-term, ice age history of the offshore region, complementing knowledge gathered onshore from adjacent north-east Norfolk.

Collectively, this new geological mapping will help a range of users understand the geology of the seabed, enabling them to make more effective and informed decisions about how to manage or interact with it.

Dr Jonathan Lee, BGS Quaternary Geologist.

The offshore East Anglia area forms an important region within the nation energy infrastructure, being a focus for successive phases of development of offshore renewables, such as windfarms, and related infrastructure. The area is also critical for marine conservation, as it hosts Europe longest known offshore chalk reef.

The new offshore East Anglia geological maps are available from BGS under the ‘fine-scale maps’ (1:10 000 scale) section of the Offshore GeoIndex, or as downloadable shapefiles for offline viewing.

Through a greater understanding of the geology below the seabed, the UK can enhance its development of offshore renewable, whilst helping to protect threatened habitats and rare species that are nationally important.

Dr Jonathan Lee.

Notes to editors

The offshore East Anglia geological maps are an interpretation of the seabed, based primarily on high-resolution bathymetric data that includes information about the depths and shapes of underwater terrain. The data is captured through the Maritime and Coastguard Agency UK .

Geological interpretation is further informed by:

• acoustic backscatter data
• grab samples and sediments
• shallow seismic data
• existing onshore and offshore geological map products

The East Anglia map forms part of aseries of new fine-scale mapsproduced by BGS which are focused on the seabed geology of the UK continental shelf.