Anomalous geomagnetic variations possibly linked with the Taiwan Earthquake (Mw= 6.4) on 19 December 2009
Anomalous geomagnetic variations possibly linked with the Taiwan Earthquake (Mw= 6.4) on 19 December 2009
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地磁异常变化可能与 2009 年 12 月 19 日台湾地震（Mw= 6.4）有关
DOI：
10.1155/2011/848467
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
S. Abe and A. Ikeda
中科院分区：
文献类型：
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作者：
Takla;E. M. ;K. Yumoto;J. Y. Liu;Y. Kakinami;T. Uozumi;S. Abe and A. Ikeda
2009年12月19日，台湾东部约45公里深处发生强烈地震（Mw = 6.4）。震中位于距离台湾花莲（HLN）车站约20公里的地方。通过分析来自HLN站和日本Amami Oshima（AMA）的数据作为远程参考，HLN站记录的地磁东西（D）和垂直（Z）分量与2009年12月AMA站记录的分量没有相关性。10-15 nT的异常变化在震前一周左右开始，持续两周左右。此外，在Pc 3（10-40秒）的范围内的增强ULF信号被观察到的地震发生前几天。此外，HLN台Pc 3振幅的偏振比（Z/H（南北分量））在地震前几天下降。这些异常变化背后的机制尚未完全了解。然而，我们预计，地壳应力扰动和地下电导率的变化与地震发挥了重要作用，产生这种观察到的地磁变化。
On 19 December 2009, the eastern part of Taiwan at approximate depth of 45 km was struck by a strong earthquake (Mw = 6.4). The epicenter was located about 20 km away from the Hualien (HLN) station in Taiwan. By analyzing data from the HLN station and Amami Oshima (AMA) in Japan as a remote reference, the geomagnetic east‐west (D) and vertical (Z) components recorded at the HLN station are showing no correlation with those at the AMA station in December 2009. Anomalous variations of~10–15 nT started about one week before the occurrence of the earthquake and lasted for about two weeks. Also, an enhanced ULF signal in the range of Pc 3 (10–40 s) was observed a few days before the onset of the earthquake. Moreover, the polarization ratio (Z/H (north‐south component)) of the Pc 3 amplitude at the HLN station decreased a few days preceding the earthquake. The mechanism behind these anomalous variations is not fully understood. However, we expect that crustal stress perturbations and underground conductivity changes associated with the earthquake played an important role for generating such observed geomagnetic variations.