During the last two decades, and thanks to combined efforts of research Institutes, Academia and Industry, great strides have been made in the area of marine geotechnics and submarine landslides. This advance was possible because of the substantial danger posed by submarine landslides to offshore structures, marine structures and coastal communities. Thanks to oil industry exploration, numerous studies and projects on submarine slope instability and its effect on offshore structures, pipelines and marine construction have been carried out on the Norwegian Margin, in the Gulf of Guinea and the Gulf of Mexico. It was often shown that conditions of seafloor instability are complex and result from interaction of many causal and triggering factors. It was also often demonstrated that an integration of geophysical, geological and geotechnical approaches are needed for a better assessment and understanding of submarine slide mechanisms.
The main objective of the present work is to report on integrated approaches used to improve submarine landslides and geohazards assessment by including multi-disciplinary study going from observation and description to more quantitative methods. Two different sites with evidence of sediment deformation and failures from the Gulf of Guinea and the Mediterranean Sea characterized, respectively, by the presence of gas hydrates and high seismicity will be presented and discussed. Developments are described in the following areas: i) field measurements and monitoring ii) causal factors and triggering mechanisms iii) advanced constitutive laws and numerical modelling and iv) uncertainties in data and knowledge.