社會脆弱性指影響個人或團體受災機率與災後恢復能力的社會特徵。在決定誰容易遭受危害衝擊的層面上，社會因素經常扮演重要的角色。然而，社會脆弱性的評估在臺灣仍然非常罕見。少數的研究也僅止於建構指標。本研究試圖檢驗社會脆弱性是否可解釋九二一地震的死亡率分布。利用因子分析法，一九九○年各鄉鎮的十六種變數可濃縮為三個因子：因子一反映社經地位較低的特徵；因子二反映人口高齡化的特徵；因子三反映失業與不完整家庭的特徵。本研究利用迴歸分析測試三個因子與九二一地震死亡率的關連。結果顯示，在相同的地震強度之下，三個因子皆與地震死亡率呈正相關。不過，僅高齡化因子達到統計顯著水準。由於地震死亡率僅反映災害的直接衝擊，關於社會脆弱性與災害後續衝擊的關連，仍有待後續研究進一步探討。

Social vulnerability means the social characteristics affecting the potential to loss in natural hazards and the ability to recover. In respect to determining who vulnerable to hazards, social factors usually play important roles. However, the assessment for social vulnerability in Taiwan is still rare and few studies have limit to construct indicators. This research examine whether social vulnerability can explain the distribution of mortality in the 921 Earthquakes. By means of factor analysis, 16 variables of each township of 1990 are reduced to 3 independent factors reflecting the characteristics of low social-economic status, aging, unemployment and incomplete family, respectively. The results of regression models show all 3 factors positively correlate to the mortality under the same seismic intensity. However, only the factor of aging achieves statistical significance level. Due to the mortality reflects only the direct impact of the disaster, the relationship between social vulnerability and the follow-up impacts after the disaster remains further investigations.