日本MW9.0地震前的舒曼谐振异常分析

2011年3月11日日本本州岛东海岸附近海域发生了M_W9.0地震. 基于中国云南的舒曼谐振(SR)观测站的磁场观测数据， 分析了与该次地震有关的SR疑似异常现象. 分析表明， 震前3—4天低阶谐振开始出现比较明显的幅度增强现象， 以2011年3月8日(北京时间)这一天的现象最明显， 南北向在7:00—10:00和12:00—15:00异常比较明显， 而东西向只在12:00—15:00异常相对比较强. 根据对2011年3月1—11日及对应每天前后各15天共41天的数据的联合分析， 3月8日部分时间段的低阶谐振磁场差明显高于一倍甚至两倍标准差; 相比而言， 正常的一天内各阶磁场差要明显低于一倍标准差. 最后， 根据一些日本地震学者提出的SR异常机理， 进一步分析了在云南观测站能观测到日本地震异常的可能性. 结果表明, 在永胜观测站可以观测到日本地震引起的一阶到三阶SR异常， 与发现的异常主要集中在低阶的现象比较吻合. 

Schumann resonance anomaly before the MW9.0 Japan earthquake

Schumann resonance (SR) anomalies related to the 11 March 2011 giant earthquake near the east cost of Honshu, Japan, were analyzed based on the data from 3 observatories in Yunnan province, China. The result reveals that the resonance amplitude was enhanced 3—4 days before the earthquake, and the most obvious anomalies occurred on March 8, when the anomalies mainly appeared during 7:00—10:00 (Beijing time) and 12:00—15:00 in NS component, and 12:00—15:00 in EW component. Based on a joint analysis of 41 days' (March 1—11 plus 15 days before and 15 days after each day) data, the amplitude increase on March 8 is 1 or 2 times higher than the standard deviation, while the variation on a normal day is far below the standard deviation. In the end, it is proved that anomalies caused by earthquakes in Japan could be observed in Yunnan according to the anomaly mechanism proposed by some Japanese scholars, and the anomalies are mainly first- to third-mode SR anomalies, which are consistent with the observed phenomenon that anomalies mainly occurred in low modes.