How to Create a VSD

Before beginning an assessment, users of the VSD must carefully define the system that they wish to study. This system must include two elements: the people or things they value that are open to harm (the exposure unit), and the coastal hazard that may cause this harm (the hazard). For example, a VSD assessment might consider the vulnerability of the elderly (exposure unit) to hurricane storm surge (hazard). Another example might be the vulnerability of coastal water supplies (exposure unit) to sea level rise (hazard). It is also usually a good idea to define the boundaries (in space and time) of the system you will be studying. Thus, rather than assessing the vulnerability of women to storm surge worldwide and at an indeterminate time in the future, you might more narrowly focus your study on the expected vulnerability of the elderly to storm surge in Florida during 2015 to 2025. Specifying a time is especially important for the analysis of coastal vulnerability, since – in addition to demographic changes to the social element – sea level rise may lead to significant changes in the physical element over time.

The description of the system – including exposure unit, hazard, place, and time – is then placed at the center of the VSD. As seen in the above example about the vulnerability of women to storm surge, this description will usually take the form of:

VULNERABILITY OF [EXPOSURE UNIT] TO [HAZARD] IN [PLACE] DURING [TIME]

The next step in completing the VSD is to brainstorm components of vulnerability for each of its dimensions (exposure, sensitivity, and adaptive capacity). Components are general descriptions of the parts of the human-environment system that shape or contribute to each of the three dimensions of vulnerability. There are typically many components that contribute to each of these dimensions. For example, the shape of a coastline and its proximity to a subduction zone are components of exposure that would affect vulnerability to tsunami. Components of sensitivity to the tsunami hazard might include both the demographics of persons in exposed coastal communities and the quality and effectiveness of warning systems and other protective infrastructure (building codes, sea walls, etc.). For adaptive capacity, components generally include resources or systems that coastal managers can draw on to reduce exposure or sensitivity, such as access to financial resources or the integrity and effectiveness of local emergency management structures. The components for each dimension are placed on the VSD in a ring that surrounds the dimensions.

The final step in completing the VSD is to brainstorm measures: ways to record, assess, or evaluate each of these abstract components. For example, measures of tsunami frequency and intensity – two components of tsunami exposure –might include the average number of years between tsunami events at a location (the return period, which is a measure of frequency) and the average height of tsunami waves at the location (which is a measure of intensity). Measures of the demographic component of sensitivity to tsunami could include information about the exposed population's age, income, or gender. Finally, measures of adaptive capacity for tsunami might include an estimate of the amount of money or number of professionals that a community has dedicated to disaster preparation and response. The measures for each component are placed on the VSD on the outermost ring, surrounding the components.

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