# Aveiro Canyon Head (Portugal) Submarine Slope Instability Assessment
## 6 Final Considerations  
The assessment of the susceptibility to the occurrence of movements in the Aveiro Canyon slopes followed methodological principles, well tested onshore [18; 28; 29; 52; 53; 54] with the necessary adaptations to the marine environment, where few studies using these kinds of statistical method are known (e.g., [2; 34; 35]). This paper aims to take one step further into the study of landslides in marine environment, one of the main dynamic processes promoting the sediment transfer to deeper domains. The statistical methods used in the present study, information value (IV) and logistic regression (LR), proved to be an adequate approach, considering the available low-resolution data. With these methods, it was possible to relate the identified instabilities with factors that may be associated with the generation of slope movements (predisposing factors). In the end, resulting models were assessed and validated through a standard statistical technique, which corresponded to the construction of a ROC curve, and calculating the respective AUC. It was also possible to verify, through the preparation of the inventory of instabilities, that they can be mainly classified as rotational slides or slumps and affects an area of about 44 km\({}^{2}\) of the seafloor, which represents 4.3% of the study area. Overall, the predisposing factors considered in this paper contributed to a good performance of both models. Bathymetry was revealed to be the most important factor in the study area, followed by mean slope angle and aspect. Although, as mentioned before, there are only a few studies made in submarine slopes, this finding is in line with the conclusions of a similar study done in Espirito Santo Basin (Brazil) [34], where bathymetry (elevation) and slope gradient were the most important factors. Although the superficial sediment mapping below the 500 m depth was extrapolative, it is clear that the type of sediments has direct influence on the triggering process of slope movements. In spite of the limitations of the database available for this work, the validation of the models obtained AUC values of 0.79 (IV) and 0.83 (LR) which is acceptable and very satisfactory models [47], respectively. LR provided better results, while IV gave another perspective on what is the weight of each factor in computing the susceptibility models. Considering that the study was addressed to marine environment, where direct observation and confirmation is not possible, the results obtained are quite promising for the assessment of submarine slope-failure susceptibility on a regional scale, enabling a preliminary assessment based on limited databases, which requires, as a minimum, bathymetry and sea bottom sedimentary cover maps. This approach may be useful for the selection of zones to be studied in more detail using purpose made site investigations (including geophysical investigations, drilling, sample collection and \"in situ\" and laboratory testing) required to support physically based slope stability analysis for specific projects. [PERSON] is responsible for the conceptualization, data processing, integration and model output, original draft writing and visualization. [PERSON] supervised the investigation and model conceptualization, the paper writing and data analysis. [PERSON] supervised the sediment data interpretation, model integration and paper writing. [PERSON] and [PERSON] have additional credits in the study administration and funding. All authors have read and agreed to the published version of the manuscript. This research was funded by FCT project UID/GEO/50019/2020 (Instituto Dom Luiz) and SEDMAR Program (Instituto Hidrografico). Multibeam data and sediment samples were acquired under the scope of SETLAT Program (funded by the Portuguese Navy) and DEEPCO project (funded by FCT, contract number POCTI/CTA/46367/2002). APC was funded by FCT project UID/GEO/50019/2020 (Instituto Dom Luiz). Acknowledgements. : Acknowledges are due to the mentioned projects and programs, for the provided data.