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• Main Authors: Yu-Hsiang Lin, 林鈺翔
• Other Authors: Jann-Yenq Liu
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/90856698546467662885

碩士 === 國立中央大學 === 太空科學研究所 === 92 === Abstract In this paper, we utilize ground based GPS receivers measured total electron content (TEC) variations of three hundred and twenty seven earthquakes in Taiwan during 1994-2003. The TEC values are further divided by their median values in order to remove the ionospheric seasonal and diurnal effects. Results show that the TEC decreases significantly and often concurrently registers pronounced decrease anomalies during 1000-2000 LT from five days prior to the earthquake day to two days after. It is also found that for M≧5.6 earthquakes, the magnitude is proportion to the TEC decrease. From the odds of the TEC decrease day prior to the earthquake day, we conclude that the anomalous day of decreasing TEC is closer to the earthquake day if the earthquake is larger. The statistics result also confirms that the larger earthquakes yield the greater odds values.