Are large submarine landslides temporally random or do uncertainties in available age constraints make it impossible to tell?

by PhD student Ed Pope

Large submarine landslides can potentially generate very destructive tsunamis and damage expensive seafloor infrastructure. Understanding their frequency and triggers is therefore important especially if it is likely to change significantly due to future climatic and sea level change. Previous work has proposed that there is strong correlation between climatic driven changes and landslide frequency. In contrast, statistical analysis of a global dataset of 41 large (>1km³) late Quaternary submarine landslide ages in the last 30 thousand years concluded that landslides have a temporally random distribution. This would suggest that landslide frequency is weakly controlled or not controlled by a single globally consistent factor such as eustatic sea level rise. However, there are considerable uncertainties surrounding the age of almost all large landslides. Our recent work has sought to analyse whether these large landslides are indeed temporally random, or whether the uncertainties in landslide ages are simply too great to tell.

Our results suggest that there are currently insufficient known events, and those that are known have uncertainties too large for us to be certain of a statistical distribution of event timing. It was also found that the use of a global database of submarine landslide occurrence may act to possibly conceal the role of global environmental influences on landslide frequency. We are therefore able to say little about the impacts of future climate change on landslide frequency from the current record.

Ed Pope