Given the disparate spatial patterns of the physical and socio-economic sub-indexes, it follows that the distinct hotspots identified in both sub-indexes may not be fully represented in the final combined sensitivity index. Major population centres located on unstable, erodable terrain (sedimentary rocks) with a low elevation appeared to be the most susceptible, and were given the highest combined index values accordingly.
The low elevation of the coastal regions surrounding the Campbell River and Nanaimo as well as the high concentration of population and roads is likely to be the reason behind the high scores of the two areas on the final index. It is interesting to note that despite the high socio-economic sub-index values in Victoria due to the high concentrations of population and infrastructure construction, the city’s low scores in the physical sub-index resulted its eventual classification as an area of generally moderate risk.
A map of the final index values is shown below. The index scores obtained after the combination of the two sub-indexes were reclassified into 5 ranks, which are defined as:
- Rank 1: 0 – <20, Very Low Risk
- Rank 2: 20 – <40, Low Risk
- Rank 3: 40 – <60, Moderate Risk
- Rank 4: 60 – <80, High Risk
- Rank 5: 80 – 100, Very High Risk