Probability of Heavy Rainfall Events in Assessing Landslide Risk for Tasmania
Abstract
Landslides are natural hazards that can have significant consequences from failure,including injury and death to people and damage to homes, infrastructure and the natural environment. Mineral Resources Tasmania has produced landslide susceptibility maps for populated regions of the State to enable risk assessment to be undertaken by stakeholders. In assessing the risk presented by landslides, it is important that the frequency of occurrence of landslides is considered, which is known to be related to the frequency of occurrence of heavy and/or prolonged rainfall events.
This paper describes the analysis that was performed to assess the probability that rainfall depths of a given magnitude will be equalled or exceeded for important locations across the State. Two different analyses of heavy rainfall were conducted, which reflect the two different mechanisms for landslides that were of interest. Maps were produced for the spatial variation in heavy rainfall probabilities that influence landslide risk across Tasmania. A site specific risk assessment was undertaken that suggests the risk of debris flow to a neighbouring community is at an unacceptable level based on societal risk criteria.
Authors
Phillip Jordan & Colin Mazengarb