THE GEOLOGICAL SURVEY OF IRELAND, IRISH NATIONAL SEABED SURVEY; MAPPING THE IRISH UNDERWATER LANDSCAPE

The Irish National Seabed Survey is a seven-year, €27 million survey of Ireland’s seabed, managed by the Geological Survey of Ireland (GSI). Ireland’s seabed area is a resource of major significance to the nation's future. Most of Ireland’s seabed is unmapped and consequently represents a large untapped resource of potential benefit to many different sectors. The Irish National Seabed Survey encompasses an area that is approximately ten times the size of Ireland's land area and represents one of the largest seabed mapping projects undertaken anywhere in the world.

The Geological Survey of Ireland, Irish National Seabed Survey is primarily a multibeam sonar survey of an area of 525,000 sq. km in size. This acoustic technique provides bathymetry data and detail of the nature of the seabed and its overlying sediment. Other techniques to evaluate the nature and structure of the seabed and the deeper geology include: magnetic and gravity measurements, deep seismic refraction studies, sub-bottom profiler, water column and current measurements, seabed sampling and ground-truthing of the multibeam dataset. The multibeam sonar remote sensing imagery and the associated data sets collected during the Irish National Seabed Survey provides a wealth of data to ocean disciplines.

To date surveying of the deeper water (4500 to 200m water depth) regions, an area of almost 410,000sq.km. to the west of Ireland, has been completed providing new and comprehensive datasets. From the preliminary maps produced it is already clear that lots of exciting and interesting results have been highlighted by the seabed survey.

* There have been indications of the existence of hydrocarbons in the form of gas escape features and mounds

* Interpretation of the backscatter maps clearly identifies both active and inactive deep-water channel complexes

* Areas of catastrophic slope failure have been identified

* Substantial numbers of mound features and ridges not previously identified have been observed in the multibeam and sub bottom profile records

* Many other low relief features such as mounds, sinuous channels, and sedimentary bedforms have been successfully resolved

* There is clear potential for studying ocean circulation patterns

* Mass data storage and processing software is in place and the provision of digital products is now possible