###### Abstract  
This paper presents a geohazard assessment along the European continental margins and adjacent areas. This assessment is understood in the framework of the seafloor's susceptibility to (i.e., likelihood of) being affected by the presence of hydrate deposits and the subsequent hazardous dissociation processes (liquefaction, explosion, collapse, crater-like depressions or submarine landslides). Geological and geophysical evidence and indicators of marine gas hydrates in the theoretical gas hydrate stability zone (GHSZ) were taken into account as the main factors controlling the susceptibility calculation. Svbalbald, the Barents Sea, the mid-Norwegian margin-northwest British Islands, the Gulf of Cadiz, the eastern Mediterranean and the Black Sea have the highest susceptibility. Seafloor areas outside the theoretical GHSZ were excluded from this geohazard assessment. The uncertainty analysis of the susceptibility inference shows extensive seafloor areas with no data and a very low density of data that are defined as critical knowledge gaps.  
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Geological event inventories are a useful tool for regional risk analysis [13]. Global gas hydrate inventories have been used to make predictions about global hydrate volumes [14; 15] and related risks [16], and to make impact projections based on future warm scenarios [17]. In the near future, marine gas hydrates will become a severe geohazard because of the unfavourable consequences of global warming on the marine gas hydrate stability field [11; 17]. They will thus trigger seafloor instabilities in gas hydrate areas that are currently stable [17], discharging marine methane from shallow near-shore environments (0-50 m) to the atmosphere [18], lowering pH and causing geochemical changes in the water column due to aerobic oxidation [19]. However, moderate methane submarine emissions are absorbed by fragile chemosynthetic ecosystems that prosper in the vicinity of venting gas seeps [20; 21]  
Evidence of marine methane hydrates has been reported in eight main regions along the European continental margins, and in adjacent areas such as offshore Greenland and Svalbard, the Norwegian margin, offshore the northern British Islands, the southern Iberian and northwest African margins (the Gulf of Cadiz and Alboran Sea), and the Black, Marmara and eastern Mediterranean seas [22]. However, hydrate-related data (geological, geophysical and oceanographic) are not homogeneously covered in the whole extent of the European continental margins. This issue is especially important for obtaining hydrate-related predictions (e.g., creating a predictive--and quick--static and continuous model for the hydrate stability field along the whole of the European continental margins).  
This paper presents, for the first time on the whole of the European margins and adjacent areas, a geohazard assessment (susceptibility analysis) of the presence of marine gas hydrates. It also assesses the main knowledge gaps of hydrate-related information with a pan-European scope, and analyses their impact on the uncertainty of susceptibility inference. Susceptibility is understood as the likelihood of the seafloor to be affected by the presence of hydrate deposits.