Proceedings of the 12th International INQUA meeting on paleoseismology, active tectonic and archaeoseismology

64 PATA Days 2024 R E S U LT S The current offshore domain is characterized by shallow bathymetric depths of less than 50 m; this domain has therefore been largely emerged throughout the Quaternary cold periods. The Holocene sedimentary prism is generally absent from the submerged platform and is concentrated on the coastline. The bottom of the Channel is therefore essentially rocky, except within deeps partially filled by thick loose sedimentary formations. Kaci et al. (2024) compiled available or recently acquired high- resolution bathymetry data (LiDAR, multibeam echosounder reaching a high resolution up to 1m). It was thus possible to identify and delineate the geological formations of the bedrock according to their fabric (roughness of the sea bottom, structural lineations, etc.), and at the same time illuminating new significant faults (Figure 2). The stratigraphic attribution of each bathymetric facies was possible thanks to their continuity with the geological formations of the coast. The mapping obtained on the area surrounding the peninsula of the Hague now appears very well resolved and comparable to the detail of a geological map at 1/50,000 (or better), contrasting with the previous version (of the order of 1/1,000,000). Beyond the precise mapping, the work Fig. 2: Geological map of the La Hague offshore domain, after the compilation of high-resolution of bathymetric data and connection to coastal geology. The map highlights post-Eocene faults, such as the La Hague Offshore Fault (LHOF) and related structures (AF: Auderville Fault and LHCF: La Hague Cape Fault). From Kaci et al. (2024).