Analysis of the short-period wave propagation in the ionosphere associated with earthquakes using 4D GPS tomography

电离层电子密度扰动是大地震后经常观测到的现象，它可以通过GPS导航卫星载波的延迟来测量。本文提出了一种利用GSI运行的GEONET的1Hz采样数据获取电离层扰动三维结构时变图像的方法。通过对2004年十胜冲地震的分析，我们证明了电离层扰动是来自地面和海面的色散声波。声波是由大规模地壳形变产生的，并到达电离层。

Ionospheric electron density disturbance that is often observed after large earthquakes can be measured from the delay of the carrier wave from the GPS navigation satellites. We developed a method to obtain the time variation images of the 3D structure of the ionospheric disturbance using 1Hz-sampling data from GEONET operated by GSI. By applying the method to the 2004 Tokachi-Oki earthquake, we have shown that the ionosphere disturbance is the dispersive sound wave from the ground and the ocean surface. The sound waves were generated by the large-scale crustal deformation and reached to the ionosphere.