Study of seismo-electromagnetic phenomena (lithosphere-atmosphere-ionosphere coupling)

主要研究结果如下：(1)日本观测数据的收集和分析研究了两个重要的物理参数：(1)超低频辐射和(2)与地震有关的电离层扰动。我们对2004年新泻地震进行了事件研究，观测到了名古屋测向确定的超低频辐射的明显前兆效应，我们可以在JJY-Kochi路径上探测到明显的前兆电离层扰动。对另一次大地震印度尼西亚苏门答腊岛地震进行了研究；我们可以确定这次地震的超低频辐射和电离层扰动。此外，对电离层扰动与地震的相关性进行了进一步的统计研究，取得了良好的效果。(2)在意大利、希腊和台湾的甚低频观测和数据分析这三个国家的甚低频观测进展良好，我们一直在继续进行数据分析。(3)岩石层-大气-电离层耦合的研究从甚低频幅度波动的频谱分析来看，我们认为大气重力波是这种耦合的最有可能的候选者。我们广泛的地面数据与法国德米特卫星数据相协调，以进一步研究岩石层-大气-电离层耦合的机制。

The main results can be summarized as follows.(1)Data collection and analysis of observational data in JapanTwo important physical parameters are studied extensively : (1)ULF emissions and (2)ionospheric perturbations associated with earthquakes. Event studies have been performed for the 2004 Niigata earthquake, for which we have observed clear precursory effect of ULF emissions as determined by direction finding at Nagoya and we could detect clear precursory ionospheric perturbations on the JJY-Kochi path. Another large earthquake, Indonesia Sumatra earthquake was studied ; we could identify both ULF emissions and ionospheric perturbations for this earthquake. Further, a statistical study further on the correlation between ionospheric perturbations and earthquakes has been undertaken with a good success.(2)VLF observation in Italy, Greece and Taiwan and the data analysisThe VLF observations in these three countries are going good, and we have been continuing the data analysis.(3)Study of lithosphere-atmosphere-ionosphere couplingWe have suggested the atmospheric gravity waves as the most likely candidate for this coupling, as evidenced from the spectral analysis of VLF amplitude fluctuation. Our extensive ground-based data have been coordinated with the French DEMETER satellite data to study further the mechanism of lithosphere-atmosphere-ionosphere coupling.