Towards an empirical vulnerability function for use in debris flow risk assessment

Abstract

Abstract. In quantitative risk assessment, risk is expressed as a function of the hazard, the elements at risk and the vulnerability. From a natural sciences perspective, vulnerability is defined as the expected degree of loss for an element at risk as a consequence of a certain event. The resulting value is dependent on the impacting process intensity and the susceptibility of the elements at risk, and ranges from 0 (no damage) to 1 (complete destruction). With respect to debris flows, the concept of vulnerability – though widely acknowledged – did not result in any sound quantitative relationship between process intensities and vulnerability values so far, even if considerable loss occurred during recent years. To close this gap and establish this relationship, data from a well-documented debris flow event in the Austrian Alps was used to derive a quantitative vulnerability function applicable to buildings located on the fan of the torrent. The results suggest a second order polynomial function to fit best to the observed damage pattern. Vulnerability is highly dependent on the construction material used for exposed elements at risk. The buildings studied within the test site were constructed by using brick masonry and concrete, a typical design in post-1950s building craft in alpine countries. Consequently, the presented intensity-vulnerability relationship is applicable to this construction type within European mountains. However, a wider application of the presented method to additional test sites would allow for further improvement of the results and would support an enhanced standardisation of the vulnerability function.

Stochastic landslide vulnerability modeling in space and time in a part of the northern Himalayas, India

“…Landslide vulnerability assessment is complicated because of the complexity in spatio-temporal modeling (Van Westen et al 2006;Birkmann 2007). In fact, vulnerability is dynamic in nature and hence should be assessed by taking both spatial and temporal aspect into consideration (Fuchs and Hubl 2007;Galli and Guzzetti 2007). Kaynia et al (2008) proposed a probabilistic estimation of landslide vulnerability that has been applied to estimate the susceptibility to structure and susceptibility of person in structure.…”

Mountain hazards: reducing vulnerability by adapted building design

“…Even though the theory of vulnerability has been subject to extensive research and numerous practical applications over the past decades, considerable gaps still exist with respect to standardized functional relationships between impacting forces due to occurring hazard processes and the structural damage caused (Fuchs et al 2007b;Papathoma-Köhle et al 2011). For a major part these gaps result from the overall lack of data, in particular concerning:…”

“…These findings support previous work carried out by Romang et al (2003). Consequently, local protection measures such as deflection walls and specially designed closure structures for at-grade openings definitely play a major role in reducing the vulnerability of buildings, particularly with respect to low and medium process intensities (Fuchs et al 2007b). …”

Vulnerability of simple reinforced concrete buildings to damage by rockfalls

“…These researchers correlated damage with landslide intensity by empirical means. Fuchs et al (2007) calculated the vulnerability of structures damaged by debris flows in the Austrian Alps, as the ratio of the monetary loss to the reinstatement value. Last, Wong et al (2004, Wong andKo 2008) derived vulnerability factors for houses by plan area by integrating the probability function of debris runout distance and a model for the degree of damage.…”