The Application of the Post-Typhoon Damage Model (Ṫ-Model) to The Typhoon Hagibis in Japan (October 2019)

We introduce a new tool to evaluate the human and economic impact of typhoons. The new applicable tool is the “post-typhoon damage Model (Ṫ-Model)”. The Ṫ-Model is based on the application of six indicators, namely (i) post-typhoon damage ratio (Ṫ(i)-Ratio); (ii) post-typhoon damage total value (Ṫ(j)-Total Value); (iii) post-typhoon damage balance (Ṫ(j)-Balance); (iv) post-typhoon damage marginal rate (Ṫ(j)-Marginal Rate); (v) post-typhoon damage critical point (Ṫ(j)-Critical Point); and (vi) post-typhoon damage surface (Ṫ(j)-Surface). The measurement of the six indicators is based, in turn, on simultaneously evaluating nine sub-variables (svi). The nine sub-variables are all defined to be within a perimeter of 10 km2. The sub-variables are number of deaths (sv1), total number of missing people (sv2), total number of sick people (sv3), total number of people with minor injuries (sv4), total number of critically injured people (sv5), total number of people evacuated(sv6), total number of people with access to water and electricity (sv7), total number of people with access to food and water (sv8), and total number of hospitalized people (sv9). The central objective of the Ṫ-Model is to evaluate the human and economic impact from a typhoon. The model generates a Microsoft excel worksheet that inputs, stores, classifies, calculates, and visualizes a typhoon’s human and economic damage within a perimeter of 10 km2. Finally, the Ṫ-Model was applied to the Hagibis typhoon which hit Japan in October 2019.