Subsurface structure affects landslide susceptibility



The likelihood of landslides on an exposed bedrock hill is dependent on the strength of the bedrock as well as the slope of the hill. In general, stronger rocks provide increased resilience against landslides and are capable of supporting steeper slopes. But for the hills of Fiordland and the Southern Alps in New Zealand that experience repeated landslides, these simple proxy measures do not tell the whole story. The hills in these two regions have similar slopes, despite the fact that they are formed from rocks with significantly different inherent strengths, and the landslides in the Southern Alps are both more powerful and more common than those in Fiordland.