Quantitative assessment of landslide frequency versus magnitude of displacement

Understanding landslide frequency is an important challenge in the process of the assessment of landslide risk. Importantly, from the perspective of landslide risk management today, this paper investigates the relationship between 'how often will a landslide move' and 'how far will it move when it does move'. Such relationships must reflect the continuum between the lower frequency 'catastrophic' type failures and the much higher frequency millimeter type magnitudes of displacement; and intervals along this continuum will likely have different management significance. So, when considering the frequency of landslide move-ment, the full question must be 'what is the frequency of a given magnitude of displacement'? Several site specific case studies will be presented highlighting both the data collected and also the subsequent analysis of this data as part of the research towards answering the question 'what is the frequency of a given magnitude of displacement'?