地磁擾動與日本東北外海地震之相關性探討

The geomagnetic fluctuation during the Tohoku earthquake

陳俊榕(Chun-Rong Chen)

指導教授 ： 顏宏元

國立中央大學/地球科學學院/地球物理研究所/碩士(2012年)

摘要

本研究將探討於日本311大地震後於台灣各測站所接收到的擾動訊號。2011/3/11 13:46於日本東北外海發生一規模9.0的大地震。地震後約於14:03在台灣各磁力測站，記錄到週期為200秒的擾動訊號。為分析造成此訊號的原因，本研究增加了中國大陸、日本、澳洲、法屬大溪地島等地的磁力資料。在日本、中國大陸等離震央的較接近的測站，都可以明顯的發現有相同的訊號出現，此訊號又隨著震央距增加而有延遲的現象出現。將各測站接收到磁力擾動訊號的時間點與震央距作圖，求得此訊號傳播速率大約為3.3 KM/S，此速度與雷利波的其中一種速度相同，因此本研究認為其與地震所產生的雷利波有關。為了探討雷利波與此訊號的關係，擷取九州、金門、蘭州、昆明、烏魯木齊等地震站之震波資料。比較地震波與地磁訊號，發現當雷利波於Z分量最大振幅與磁力擾動出現時間，大約相差280秒。此一關係，更加確信磁力擾動訊號是來自於大地震的雷利波。本研究將針對此一關係去做探討，以解釋地磁擾動訊號產生的原因。

關鍵字

日本東北外海地震 ； 地磁場

並列摘要

Taiwan established a network of geomagnetic stations since 2002. This network recorded geomagnetic with 1 sample per second. 2011/3/11 13:46:23(UTC+8), a large earthquake occurred in north-east Japan. After the earthquake, a special geomagnetic fluctuation was recorded by the Taiwan’s geomagnetic network. After compare with the geomagnetic record in the other world-wide geomagnetic station, we can confirm this geomagnetic fluctuation is not cause by an external source. This fluctuation is similar with the record in Sumatra earthquake (Iyemori, 2005).The event was determined into the Acoustic-Gravity wave trigger by the Rayleigh wave. In our study, we collect the Doppler Radar System and Seismic data to compare with the geomagnetic fluctuation. Try to find out the relation between the earthquake event and the geomagnetic fluctuation.

並列關鍵字

geomagnetic ； Tohoku

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