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已知大地震辐射的面波通过动力耦合会引发向上传播穿过中性层和电离层的大气次声波。过去,利用多种技术,例如高频多普勒探测或者GPS接收器,已在电离层高度探测到这种波。高频多普勒技术对瑞雷波在电离层中的特征波形非常敏感,因而此处被用来说明与2005年3月28日苏门答腊地震(M=8.6)之后瑞雷波R1和R2震相传播一致的电离层扰动。就我们所知,这是第一次在电离层观测到R2震相。另外,我们在文中还证实超视距(OTH)雷达也观测到了电离层中R2的特征波形。而这种雷达在过去从未用于检测电离层中的地震特征波形。将超视距雷达加入到“电离层地震仪”的名单之中,我们讨论并比较了上述三种不同装置,即高频多普勒探测、GPS接收器和超视距雷达的性能。
It is known that surface waves radiated by large earthquakes initiate the atmospheric infrasound propagating upwards through the neutral and ionosphere through dynamic coupling. In the past, such waves have been detected at ionospheric altitudes using a variety of techniques, such as high-frequency Doppler detection or GPS receivers. The high-frequency Doppler technique is very sensitive to the Rayleigh wave eigenfunctions in the ionosphere and is therefore used herein to illustrate that the phases of the Rayleigh waves R1 and R2 after the Sumatra earthquake (M = 8.6) on March 28, 2005 Propagate consistent ionospheric disturbances. To our knowledge, this is the first observation of the R2 phase in the ionosphere. In addition, we also confirm in the text that the over-the-horizon (OTH) radar also observes the characteristic waveform of R2 in the ionosphere. Such radar has never been used in the past to detect seismic signature waveforms in the ionosphere. By adding OTH radar to the list of “ionospheric seismometers,” we discuss and compare the performance of these three different devices, namely, high-frequency Doppler detection, GPS receivers and OTH radar.