土壤液化潛勢區公布對房價之影響

The Impact of Disclosing Soil Liquefaction Information on Housing Price

2016年2月6日的美濃大地震，使國人開始意識到土壤液化對於居住安全的威脅。其後，政府公布八個縣市的土壤液化潛勢區查詢系統，將土地劃分為高、中、低三等級潛勢區，提高民眾對土壤液化的風險意識及居住安全的重視。然此舉卻引發市場熱議，土壤液化與房價之間的關係出現兩種討論：部分認為查詢系統之公布將衝擊房屋市場，使潛勢區內之房價下跌、成交量萎縮；另一方則考量建築技術上可以克服以及資訊透明化後的資訊疲乏，認為土壤液化於房價的影響有限。過去國內外有不少文獻針對突發事件對於特定市場的衝擊進行評估，但很少針對土壤液化對於不動產市場做相關的研究。本研究採用2015年3月至2017年2月之不動產實價登錄交易資料，及中央地質調查所土壤液化潛勢查詢系統之圖資進行實證分析。應用特徵價格理論和差異中之差異配對分析法（DID with Matching），研究臺北市潛勢地區內之房屋交易價格是否存在差異，以及比較公布前後之價格變化。實證結果顯示，政府揭露液化潛勢區之資訊，確實造成臺北市高潛勢區內之房屋價格下跌3.34%，中、低潛勢區內之房屋價格則無顯著影響，而此影響效果在公布半年後有淡化的現象。 In Taiwan, public awareness of soil liquefaction and its ensuing hazard has increased since the Meinung earthquake in 2016. After this event, the government established a Soil Liquefaction Potential Inquiry System for eight countries. Such an announcement has raised the public's perceived risk of soil liquefaction and their attention to the safety of living. Some believe that the announcement will cause home prices and real estate transaction volume to decrease in the affected areas. However, taking the modern construction techniques and the symptoms of information fatigue into account, others argue that the effect on the housing market will be limited. Several previous empirical studies have assessed the impact of the hazard on specific markets but seldom did they focus on the relationship between soil liquefaction and housing prices. This study aims to examine the effect of different potential levels of soil liquefaction on housing prices, and probes into the change before and after the disclosure of Soil Liquefaction Inquiry System. Hedonic price theory and difference-in-differences (DID) method with matching were used to analyze sales prices in a sample of real estate sold in Taipei City from March, 2015 to February, 2017. The statistical result shows that the disclosure of information on soil liquefaction potential has decreased housing prices in the high-potential areas of Taipei by 3.34%; whereas, this effect became weaker half a year after the announcement. In areas with medium and low potential, the disclosure did not significantly affect housing prices.