  Recent studies have shown that giant landslides seem to be correlated with
climatic variations. Nevertheless, the precise processes that are involved in
this phenomenon need to be better constrained. In this study, the causes of
giant landslides are investigated using a modeling approach. Here, we show that
the effect of meteoritic water infiltration could be discriminated from that of
sea-level rise on triggering paleolandslides. It is possible to identify the
cause of coastal paleolandslides based on the age of occurrence and comparison
with climatic signals when glacial maxima are more humid than during
interglacial times, as in Polynesia and East Equatorial Africa, but not in
other cases (Caribbean, Indonesia). The role of pore pressure variations and
sea-water loading variations has been discussed. The interaction between the
relative sea-level rise, preexisting relief and deep weak structure due to the
presence of highly weathered lavas may trigger the conditions for a large
landslide. Highly weathered lavas have very low friction angles at depth in
volcanic islands. When volcanoes are still actives, pressure variation of the
magma chamber caused by sea-level lowering is expected to play a significant
role in destabilization of the relief. Competing processes in real cases cause
difficulties to discriminate between these processes.
