Measuring vulnerability is a key to effective risk reduction and the promotion of a culture of disaster resilience. Kofi Annan underlined the fact that hazards only become disasters when people´s lives and livelihoods are swept away (Annan 2003). Instead of defining disasters primarily as physical occurrences, requiring largely technological solutions, disasters are better viewed as a result of the complex interaction between a damaging physical event (e.g. floods, droughts, fire and storms) and the vulnerability of a society, its infrastructure, economy and environment, which are determined by human activities. The promotion of a disaster resilient society requires a paradigm shift from the focus on natural hazards and their quantification towards the assessment and ranking of various vulnerabilities of affected societies, economies and environments (Bogardi, Birkmann 2004). BIRKMANN AND BOGARDI developed a conceptual model (BBCmodel) to understand vulnerability as a key component within the hazardvulnerability risk chain. The BBC model views vulnerability within a feedback loop system. One of the most important aspects of the BBC-concept is the fact that the conceptual model shows that vulnerability analysis goes beyond the estimation of the deficiencies and the probability of loss, disruption and injury. Within the framework of a feedback loop system the BBC-concept shows the need to focus simultaneously on vulnerabilities, existing coping capacities and takes into account the potential actuation tools to reduce the vulnerabilities related to the three key thematic areas, the social sphere, the economic sphere and the environmental sphere.

Through the analysis of probable losses and deficiencies as well as the potential intervention measures and already existing coping capacities, the BBC-concept promotes a problemsolving perspective, stressing the necessity to be proactive to reduce vulnerability before an event strikes the society, economy or environment (t=0) (see figure). The implementation of methods and tools to measure vulnerability is complex, since many loss categories are difficult to capture. While the measurement of direct fatalities and economic losses due to extreme events like tsunami and major floods is a common standard, the impacts of minor events as well as the long term impacts of floods and coastal hazards to the social and environmental sphere are not well understood. Moreover, a pro-active vulnerability assessment requires the analysis before the disaster occurs. That means new methods are needed in order to estimate the potential susceptibility and coping capacity of the affected society, economy and environment. In this context one has to consider the fact that different hazard types (floods, under-flooding, coastal hazards, tsunami etc.) require different vulnerability assessment tools and indicators. While the tsunami event with its low frequency (every 200-300 years) in Sri Lanka revealed the enormous vulnerability of coastal communities, the problem of under-flooding in Russia causes minor damages, but implies a high frequency. Although the damages in Russia with regard to under-flooding are lower, the annual frequency of underflooding in the Volga region requires adequate mitigation and preparedness strategies. Flooding and coastal hazards imply different vulnerabilities and therefore require different coping capacities. Coping strategies and coping capacities not only differ between different countries and regions, but also between various social groups. Overall effective mitigation and preparedness strategies have to be based on vulnerability assessment. Moreover, also response and coping strategies should be assessed with regard to their vulnerabilities. This is evident for example for the discussion of buffer zones in Sri Lanka. While some coastal communities will become less vulnerable to the coastal hazard, others will face new vulnerabilities if their location is faraway from their markets and business places.