This report is a contribution to the Strategic Environmental Assessment (SEA4) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change). The report describes the field of mud diapirs in the northern part of the SEA4 area, known as the Pilot Whale Diapirs, which were mapped during a multibeam survey carried out in 2002. A diapir is a fold or dome caused by more plastic rocks at depth, such as salt or mud, intruding overlying denser rocks, generally driven by their own buoyancy. Sometimes a diapir breaks through to the seafloor. The diapir field extends over an area some 60 km across, creating a very variable seabed terrain. The largest diapirs have produced elevations at the seafloor of more than 120m. The largest diapirs in the group are thought to have intruded to the seafloor from 500m or more beneath it. The evidence suggests that the diapirism was initiated between 5 and 1 million years ago, but it does not appear to be continuing at the present time.

As part of as part of the Department of Trade and Industry's (now Department of Energy and Climate Change) Strategic Environmental Assessment (SEA2) a geophysical survey was carried out in three different quarters of the North Sea: Norfolk Coast (Area 1), Dogger Bank (Area 2) and Fladen Ground (Area 3) from Kommandor Jack SEA2 Survey Leg 1, 2001. Multibeam, sidescan sonar and chirp seismic data were collected. The survey was carried to identify potential offshore Special Areas of Conservation (SACs). It was necessary to acquire data on specific features identified in the EU Habitats Directive, such as sandbanks and pockmarks, some of which might subsequently be defined as SACs. The survey was carried out in two legs. Leg one included the geophysical surveys in three different quarters of the North Sea as well as the charting which was used to guide the sampling and photographic work on the second leg. The following data are available - 25 files of processed multibeam data. Screenshots of backscatter processing are also available. Side-scan mosaics. Images are available from 15 boxes. Processed seismic data. Cruise report

As part of the Department of Trade and Industry's (now Department of Energy and Climate Change) Strategic Environmental Assessment (SEA2), this report briefly describes the evidence for the origin of shallow gas in Outer Moray Firth open blocks 15/20c and 15/25d. Sea floor pockmarks are known to occur within these blocks, and they indicate the seepage of gas from shallow levels into the local water column. An environmental concern is that any industry activity in these blocks must not plumb into any component of the system that is sustaining the gas seepages at sea bed. The study area covers two part-blocks within the eastern part of the Witch Ground Graben within the UK Central North Sea. This study follows on from the DTI 2001 SEA research on pockmarks.

This report is a contribution to the Strategic Environmental Assessment (SEA5) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change). This report reviews published and newly-acquired seabed geological data in an area of 78,000 square kilometres extending from the coast to more than 200 m water depth to the east of the British Isles. While it can be argued that the modern environment is a product of past environmental conditions, the basis for the review is also that our understanding of the modern environment can be significantly improved if new techniques, data and ideas are applied to a revision of the existing research knowledge. The purpose of the review is to place the characteristics of the seabed features that were surveyed by the DTI in 2003, and the processes forming them, into an improved understanding of their historical, local and regional context. In the summer of 2003 the DTI carried out new surveys in order to collect environmental information in 6 project areas in SEA5 and 2 project areas in SEA4. The survey data included multi-beam bathymetry, sidescan sonar, seismic reflection profiles, sea-floor photographs and samples.

As part of the Department of Trade and Industry's (now Department of Energy and Climate Change) Strategic Environmental Assessment (SEA6) a geophysical survey was undertaken on SV Meridian SEA6 Survey B (or Leg 2) in the Irish Sea between Ireland and the Isle of Man and at the north of Wales. Multibeam, sidescan sonar and chirp seismic data were collected. 11 processed gridded multibeam files are available. Raw data are also available. 11 sidescan mosaic tif files available. Raw seismic data are also available. Cruise reports are available.

This report is a contribution to the Strategic Environmental Assessment (SEA5) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change). This report reviews published and newly-acquired seabed geological data in an area of 78,000 square kilometres extending from the coast to more than 200 m water depth to the east of the British Isles. While it can be argued that the modern environment is a product of past environmental conditions, the basis for the review is also that our understanding of the modern environment can be significantly improved if new techniques, data and ideas are applied to a revision of the existing research knowledge. The purpose of the review is to place the characteristics of the seabed features that were surveyed by the DTI in 2003, and the processes forming them, into an improved understanding of their historical, local and regional context. In this way a strong element of the review is to include the results from exploration and discovery. The survey data included multibeam, sidescan sonar, seismic-reflection profiles, sea floor photographs and samples.

This report is a contribution to the Strategic Environmental Assessment (SEA6) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change). Methane-derived authigenic carbonate (MDAC) is formed as a consequence of the anaerobic oxidation of methane by consortia of bacteria. MDAC develops as a rock-like concretion when a carbonate precipitate cements normal seabed sediment; the carbon of this carbonate is derived from methane. It occurs as crusts or slabs at the seabed, or as exposed lumps. The occurrence of MDAC is evidence of methane seepage, although the seepage is not necessarily going on at the present time. Large quantities of MDAC indicate that methane seepage has occurred over a prolonged period of time. 'Submarine structures formed by leaking gas' have been identified by the European Commission's Habitats Directive as habitats worthy of protection. The distribution of MDAC in UK waters is poorly known. This report summarises the available information relevant to MDAC in the SEA6 area, including data acquired by surveys specifically conducted in support of this SEA in 2004. Carbon isotope data for samples recovered in 2004 have confirmed that the cemented hard grounds from two of the areas studied, Texel 11 and Holden's Reef, are composed of MDAC.

This report is a contribution to Strategic Environmental Assessment SEA2 conducted by the Department of Trade and Industry (now Department of Energy and Climate Change) and it reviews the distribution and character of pockmarks - shallow seabed depressions - which are common in the area of the North Sea to the north-east of Scotland known as the Fladen Ground. Pockmarks are believed to be produced by the escape of fluids (gas or water, but generally gas in the North Sea) from the seafloor and are found in areas where the seabed sediments are soft, silty clays. Processes of pockmark formation, their geometry, age and distribution, and the sources of gas in the underlying geological strata are discussed. While the great majority of pockmarks are inactive at the present time, a few are observed to be actively seeping gas. In order to provide a stronger basis upon which the significance of pockmarks within mature oil and gas provinces of the North Sea might be assessed, the Department of Trade and Industry commissioned the acquisition of new data directed towards increasing the scientific understanding of sandbanks and pockmarks as part of the SEA2 process. The survey vessel Kommandor Jack was chartered in April 2001 and, among other operations, conducted high-resolution geophysical surveys of pockmarks in the Fladen Ground. Preliminary results from that operation are included in this report.