aba64100-c106-4de3-e044-0003ba6f30bd English dataset Mary Mowat British Geological Survey (BGS) +44 (0)131 667 1000 +44 (0)131 668 4140 offshoredata@bgs.ac.uk pointOfContact 2011-08-30 MEDIN Discovery Metadata Standard Version 2.3.5 urn:ogc:def:crs:EPSG::4326 OGP 2005 Strategic Environmental Assessment SEA2 Investigation of the origin of shallow gas in Outer Moray Firth open blocks 15/20c and 15/25d 2005-02-01 publication BGS_SEA_16 British Geological Survey 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. Paul Henni British Geological Survey (BGS) +44 (0)131 667 1000 Murchison House, West Mains Road Edinburgh EH9 3LA UK offshoredata@bgs.ac.uk custodian Department for Energy and Climate Change (DECC) +44 0300 060 4000 +44 (0) 1823 284077 Admiralty Way London SW1A 2HD UK enquiries@decc.gsi.gov.uk originator notPlanned Documents NDGO0001 Habitat characterisation Industrial activity Seismic reflection SeaDataNet Parameter Discovery Vocabulary 2011-03-25 revision Geology GEMET - INSPIRE themes, version 1.0 2008-06-01 publication crust sediment SeaVoX Vertical Co-ordinate Coverages 2008-06-01 publication The SEAs data were produced as part of the UK Department of Energy and Climate Change's Offshore Energy Strategic Environmental Assessment programme; Crown Copyright, all rights reserved. The DECC SEA must be acknowledged in any maps or publications that make use of the data. All the data files are freely available to the public. The Strategic Environmental Assessment (SEA) data portal provides free access to available data and reports which have been produced through the SEA process. The site is run and managed by BGS on behalf of the Department of Energy and Climate Change (DECC). Many files can be downloaded directly from this website. Those that are too large to download can be ordered via the website for postal delivery from BGS. BGS (NERC) has been contracted by DECC to publish SEA datasets on its behalf. All intellectual property rights (including , without limitation, copyrights, database rights and all other rights which subsist or may at any time in the future subsist in the Dataset(s)) in the Dataset(s) ('Intellectual Property Rights') are owned by DECC (formerly the Department of Trade and Industry, and the Department for Business, Enterprise and Regulatory Reform). BGS has been authorised by DECC to use SEA datasets for all purposes but on a 'not-for-profit basis'. BGS has been authorised by DECC to pass on SEA datasets to third parties so that they can use them for all purposes but on a 'not-for-profit' basis. intellectualPropertyRights 5 English environment geoscientificInformation oceans SeaVoX salt and fresh water body gazetteer 2006-01-01 revision North Sea -1.9 3.3 52.8 61.8 2005-01-01 2005-01-01 http://www.offshore-sea.org.uk/site/index.php http://www.bgs.ac.uk/data/sea/home.html Strategic Environmental Assessment (SEA) data portal The Strategic Environmental Assessment (SEA) data portal provides free access to available data and reports which have been produced through the UK Department of Energy and Climate Change SEA process. The site is run and managed by BGS on behalf of the Department of Energy and Climate Change (DECC). Many files can be downloaded directly from this website. Those that are too large to download can be ordered via the website for postal delivery from BGS. download dataset This report was compiled by the British Geological Survey as part of the UK Department of Energy and Climate Change's Offshore Energy Strategic Environmental Assessment programme. The study comprised three main tasks: A desk study based on publications in the literature and unpublished reports to determine whether or not there is already a consensus on the derivation of the gas seepages in blocks 15/20c and 15/25d; A quick interpretation of available BGS shallow seismic data and commercial site survey data to determine the extent of the gas in the shallow subsurface.; Quick interpretation of appropriate horizons on the PGS MegaSurvey for indications of gas seepages from deeper levels. Use of seismic attribute analysis to map the locations of Tertiary channels that might be acting as migration conduits into the area. Investigate for gas chimneys, faults extending to shallow levels, amplitude anomalies, evidence for sediment remobilisation and any other evidence for upward gas migration into the shallow subsurface.