安通溫泉位在池上斷層東南方約3公里。池上斷層位在東台灣花東縱谷南段歐亞大陸板塊及菲律賓海板塊交界處之活動斷層。安通溫泉約為數平方公里之小面積低孔隙率裂隙含水層。自2003年7月起至今在安通溫泉已捕捉到三次地下水水氡濃度異常下降，（1）2003 地震矩規模（Mw）= 6.8 成功地震,（2）2006 Mw= 6.1 台東地震, 及（3） 2008 Mw = 5.4 安通地震。以上三次地震震央分別距離安通溫泉水氡監測井（D1） 24 公里、52公里和13公里。在以上三次大地震前，地下水水氡濃度分別從背景值787 ± 42、762 ± 57和 700 ± 57 pCi/L降至最低值326 ± 9、371 ± 9和480 ± 43 pCi/L。類似安通溫泉被延展性泥質地層包圍之脆性低孔隙率裂隙含水層之地質條件合適捕捉地下水水氡濃度異常下降的地震前兆。根據地下水水氡揮發逸散至岩石裂隙之機制及數學模式，以上三次地震前兆觀測到的地下水水氡濃度最低值及地震矩規模可用簡單的經驗關係式表示，幫助在花東縱谷南段預警破壞性地震的來臨。

The active Chihshang fault in the southern segment of longitudinal valley of eastern Taiwan is part of the suture boundary between the Eurasia plate and the Philippine Sea plate. Radon anomalies in groundwater were recorded prior to three major earthquakes – (1) 2003 earthquake magnitude (Mw) = 6.8 Chengkung, (2)2006 Mw = 6.1 Taitung, and (3) 2008 Mw = 5.4 Antung. The epicenters were located 24 km, 52 km, and 13 km, respectively, from the radon-monitoring well (D1) in the Antung hot spring about 3 km southeast of the Chihshang fault. Prior to the three major earthquakes, radon decreased from background levels of 787 ± 42, 762 ± 57, and 700 ± 57 pCi/L to minima of 326 ± 9, 371 ± 9, and 480 ± 43 pCi/L, respectively. Based on the radon-volatilization model, this paper correlates the observed radon minima with earthquake magnitude and crust strain. The correlation is a useful means of forecasting local disastrous earthquakes in the southern segment of longitudinal valley of eastern Taiwan.

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