*Jann-Yenq Liu¹、Yi-Ben Tsai²、Chieh-Hung Chen³、Yuh-Ing Chen⁴ (1.Institute of Space Science, National Central University, Taiwan、2.Department of Earth Sciences, National Central University,Taiwan、3.Department of Earth and Environmental Sciences, National Chung Cheng University, Taiwan、4.Institute of Statistics, National Central University, Taiwan)