Faculty of Economics and Law, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan.
Faculty of Economics, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan.
Risk Anal. 2020 Sep;40(9):1811-1830. doi: 10.1111/risa.13525. Epub 2020 Jun 7.
Disasters often cause exogenous flow damage (i.e., the [hypothetical] difference in economic scale with and without a disaster in a certain period) to production ("supply constraint"). However, input-output (IO) analysis (IOA) cannot usually consider it, because the Leontief quantity model (LQM) assumes that production is endogenous; the Ghosh quantity model (GQM) is considered implausible; and the Leontief price model (LPM) and the Ghosh price model (GPM) assume that quantity is fixed. This study proposes to consider a supply constraint in the LPM, introducing the price elasticity of demand. This study uses the loss of social surplus (SS) as a damage estimation because production (sales) is less informative as a damage index than profit (margin); that is, production can be any amount if without considering profit, and it does not tell exactly how much profit is lost for each supplier (upstream sector) and buyer (downstream sector). As a model application, this study examines Japan's largest five earthquakes from 1995 to 2017 and the Great East Japan Earthquake (GEJE) in March 2011. The worst earthquake at the peak tends to increase price by 10-20% and decrease SS by 20-30%, when compared with the initial month's prices/production. The worst damage tends to last eight months at most, accumulating 0.5-month-production damage (i.e., the sum of [hypothetical] differences in SS with and without an earthquake [for eight months] is 50% of the initial month production). Meanwhile, the GEJE in the five prefectures had cumulatively, a 25-month-production damage until the temporal recovery at the 37th month.
灾害通常会对生产造成外生流量损失（即某一时期有无灾害的经济规模差异）（即“供给约束”）。然而，投入产出（IO）分析（IOA）通常无法考虑这一点，因为列昂惕夫数量模型（LQM）假设生产是内生的；高希数量模型（GQM）被认为是不可信的；而列昂惕夫价格模型（LPM）和高希价格模型（GPM）则假设数量是固定的。本研究提出在 LPM 中考虑供给约束，引入需求价格弹性。本研究使用社会总剩余损失（SS）作为损害估计，因为与利润（边际）相比，生产（销售）作为损害指标的信息量较少；也就是说，如果不考虑利润，生产可以是任意数量，而且它并不能准确地告诉每个供应商（上游部门）和买家（下游部门）损失了多少利润。作为模型应用，本研究考察了 1995 年至 2017 年日本发生的五次最大地震以及 2011 年 3 月的东日本大地震（GEJE）。与最初月份的价格/产量相比，峰值时最严重的地震往往会使价格上涨 10-20%，使 SS 下降 20-30%。最严重的破坏往往最多持续八个月，累计造成 0.5 个月的产量损失（即，如果没有地震，[假设]地震期间和期间的 SS 差异之和[八个月]为初始月产量的 50%）。与此同时，五个县的东日本大地震累计造成 25 个月的产量损失，直到第 37 个月才出现暂时恢复。
