摘要
Over the last century,abnormal electromagnetic(EM)emissions associated with earthquake(EQ)activities have been widely reported and recorded by ground-based and satellite observations.However,the frequency at which abnormal EM emissions have been detected varies.In addition,whether low Earth orbit(LEO)satellites can detect EM anomalies from EQs remains controversial.In this paper,we take the Yushu earthquake as an example to address these concerns by DEMETER satellite observations and a newly constructed lithosphere-atmosphere-ionosphere model of extremely low frequency(ELF)wave propagation.The results illustrate that the frequency of ELF EM anomalies of the Yushu earthquake is mainly at 200–400 Hz.The observations and simulations illustrate that the power-frequency curve of the ELF EM wave from an underground source has a peak power frequency at 200–400 Hz,which is significantly different from the ELF EM wave radiated from the ground source.
基金
supported by the National Institute of Natural Hazards,Ministry of Emergency Management of China(Grant No.ZDJ2020-06)
the Institute of Geophysics,China Earthquake Administration(Grant No.DQJB19B27)
the National Natural Science Foundation of China(Grant Nos.41704156,41874174,41804156)
the China Research Institute of Radiowave Propagation(Research on low ionosphere satellite detection and Research on the coupling mechanism of lithosphere-atmosphere-ionosphere alternating electric field),the National Key R&D Program of China(Grant No.2018YFC1503501)
the Asia-Pacific Space Cooperation Organization(APSCO)Earthquake Research Project PhaseⅡ。
