3D seismics are now widely used in areas of intensive oil exploration, being a relatively recent technique that provides a powerful tool for detailed investigation of the often complex geometry oi sedimentary basins. The present study is concerned with the use of this technique to investigate a graben inversion structure in the southern North Sea. The North Sea is a geological province with a wide variety oi sedimentary basins, ranging in age from the Paleozoic to the Quaternary, comprising an area largely covered by geological and geophysical surveys carried out during intensive oil industry exploration. Grabens were developed during the Mesozoic in a crustal segment previously formed by the Caledonian and Hercynian orogenies, then tectonically inverted during the Late Cretaceous and Tertiary. In the southern North Sea, the Broad Fourteens Basin (or ＇＇Graben de La Haye＇＇) is a spectacular example of a very inverted graben. The Zechstein Salt, which is intercalated between basement and cover, provides a decollement layer observed to the north oi this graben but not in the south. This layer is responsible for the various types of inversion structure found out in the graben A study of the inversion oi the Broad Fourteens Basin was carried out using the data from 2D as well as 3D seismic techniques. The data from 3D seismics are used to analyse the details of fault kinematics during inversion, as well as the influence of the decollement layer on the development oi major structures, particularly the thrusts. The inversion of the Broad Fourteens Basin took place through dextral strike-slip faulting. Because the salt layer leads to a detachment between basement and cover, it is possible in places to observe the presence of two contrasting tectonic regimes - compressive in the basement and distensive in the cover. According to their shape, salt diapirs have contributed to the different styles of deformation; cylindrical diapirs are only slightly deformed, whereas walls of salt extending parallel to the graben boundaries lead to the setting and development of thrusts.