In the field of disaster prevention, disaster loss is often classified into “direct loss” and “indirect loss.” As such, “total loss” is often calculated as a sum of “direct loss” and “indirect loss,” where “direct loss” is defined as a “loss of capital (assets) as a stock” and “indirect loss” is defined as “loss arising out of decline in postdisaster production as a flow.” However, the loss here is calculated twice. The calculation is incorrect if “indirect loss” refers to, in particular, the lost profit of a firm that has lost a production facility that is considered as a stock. The reason is that the “value of capital stock” is nothing but the present value of a product that the stock will produce in the future. Therefore, an “indirect loss” defined in the above manner corresponds to a decrease in stock value. Using a dynamic economic model, this article provides a basic structure, “value of loss in capital stock lost by a disaster” = “total decline of production after a disaster.” This article also presents a relational expression in consideration of the restoration cost of a production facility, and concludes that a more multifaceted and functional damage information system needs to be developed in the future.

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