Astafyeva E, Shults K
Institut de Physique du Globe de Paris, Paris Sorbonne-Cité, CNRS UMR 7154 Paris Cedex France.
J Geophys Res Space Phys. 2019 Jan;124(1):534-543. doi: 10.1029/2018JA026107. Epub 2019 Jan 8.
Up to now, the possibility to obtain images of seismic source from ionospheric Global Navigation Satellite Systems (GNSS) measurements () has only been demonstrated for giant earthquakes with moment magnitude Mw ≥ 9.0. In this work, we discuss difficulties and restrictions of this method, and we apply for the first time the seismo-ionospheric imagery for smaller earthquakes. The latter is done on the example of the Mw7.4 Sanriku-oki earthquake of 9 March 2011. Analysis of 1-Hz data of total electron content (TEC) shows that the first coseismic ionospheric disturbances (CID) occur ~470-480 s after the earthquake as TEC enhancement on the east-northeast from the epicenter. The location of these first CID arrivals corresponds to the location of the coseismic uplift that is known as the source of tsunamis. Our results confirm that despite several difficulties and limitations, high-rate ionospheric GNSS data can be used for determining the seismic source parameters for both giant and smaller/moderate earthquakes. In addition to these seismo-ionospheric applications, we raise several fundamental questions on CID nature and evolution, namely, one of the most challenging queries-can moderate earthquake generate shock-acoustic waves?
到目前为止，通过电离层全球导航卫星系统（GNSS）测量获取震源图像的可能性仅在矩震级Mw≥9.0的特大地震中得到了验证。在这项工作中，我们讨论了该方法的困难和局限性，并首次将地震电离层成像应用于较小规模的地震。这是通过2011年3月9日Mw7.4的三陆冲地震的实例来完成的。对总电子含量（TEC）的1赫兹数据的分析表明，同震电离层扰动（CID）首次出现在地震发生后约470 - 480秒，表现为震中东北偏东方向的TEC增强。这些首次CID到达的位置与被称为海啸源的同震隆升位置相对应。我们的结果证实，尽管存在一些困难和限制，但高速电离层GNSS数据可用于确定特大地震以及较小/中等规模地震的震源参数。除了这些地震电离层应用之外，我们还提出了几个关于CID性质和演化的基本问题，即最具挑战性的问题之一——中等规模地震能否产生激波 - 声波？
