Giant landslides, mega-tsunamis, and paleo-sea level in the Hawaiian Islands

Abstract

Landslide tsunami simulations have advanced to the point where the tsunamigenic potential of giant submarine landslides (GSL) can be affirmed, while the subsidence history of different Hawaiian Islands is still subject to debate. We show that mega-tsunamis are a sufficient explanation for the observed pattern of debris height of calcareous marine deposits on some of the Hawaiian Islands. Further, our tsunami simulations, using the Alika GSL as example, can be used to reduce the considerable uncertainty in subsidence history of the different Hawaiian Islands, a current obstacle to interpreting the deposits from large waves. We also show that the onset of interglacials provides a probable explanation for the timing of these giant landslides over at least the last five million years. The climate change mechanism both explains the confusion with eustatic sea-level rise and provides a reasonable triggering mechanism for giant landslides from oceanic island volcanoes.