Department of Physics, Tokyo Gakugei University, Tokyo, Japan.
Earthquake Research Institute, the University of Tokyo, Japan.
Sci Rep. 2016 Dec 1;6:37989. doi: 10.1038/srep37989.
Ionospheric plasma disturbances after a large tsunami can be detected by measurement of the total electron content (TEC) between a Global Positioning System (GPS) satellite and its ground-based receivers. TEC depression lasting for a few minutes to tens of minutes termed as tsunami ionospheric hole (TIH) is formed above the tsunami source area. Here we describe the quantitative relationship between initial tsunami height and the TEC depression rate caused by a TIH from seven tsunamigenic earthquakes in Japan and Chile. We found that the percentage of TEC depression and initial tsunami height are correlated and the largest TEC depressions appear 10 to 20 minutes after the main shocks. Our findings imply that Ionospheric TEC measurement using the existing ground receiver networks could be used in an early warning system for near-field tsunamis that take more than 20 minutes to arrive in coastal areas.
在大型海啸之后，通过测量全球定位系统（GPS）卫星与其地面接收器之间的总电子含量（TEC），可以检测到电离层等离子体干扰。在海啸源区上方会形成持续数分钟到数十分钟的 TEC 凹陷，称为海啸电离层空洞（TIH）。在这里，我们描述了由日本和智利的七次海啸引发的 TIH 引起的初始海啸高度与 TEC 凹陷率之间的定量关系。我们发现 TEC 凹陷的百分比与初始海啸高度相关，最大的 TEC 凹陷出现在主震后 10 到 20 分钟。我们的研究结果表明，利用现有的地面接收站网络进行电离层 TEC 测量，可以用于近场海啸的预警系统，因为近场海啸需要 20 多分钟才能到达沿海地区。
