A Study of the Electric Field Before the Wenchuan 8.0 Earthquake of 2008 Using Both Space‐Based and Ground‐Based Observational Data with Spectral Element Method Simulation

Abstract

We studied the changes of the electric field before the Wenchuan Ms8.0 earthquake of 2008 using both space‐based and ground‐based observational data and the method of marginal spectra. The evolution of marginal spectra of the electric field from the repeat orbits and continuous orbits reveals that the marginal spectrum of the electric field in the ionosphere had a remarkable increase (about 1~2 orders of magnitude) from 27 April, 2008 to the time when the Wenchuan earthquake happened. For the evolution of marginal spectra of the electric field from the ground‐based data, the marginal spectrum of the Songshan station of Sino‐French cooperation began to enhance (increased by 2 orders of magnitude) from 25~29 April 2008. Such a phenomenon appeared at Chengdu, Longnan and Tianshui stations (increased by 2 orders of magnitude) from 10~14 April 2008. Despite that the marginal spectrum enhancement was identical at Chengdu, Longnan and Tianshui stations, it ended at different times. The process ended earlier at the Songshan and Tianshui stations than the Chengdu and Longnan stations. It seems that the enhancement of marginal spectra of both the ground and space electric fields happened at a roughly same time.

Simulation of a lithosphere-atmosphere-ionosphere electromagnetic coupling prior to the Wenchuan MS8.0 earthquake

“…The fact that abundant electromagnetic emissions on ULF-ELF electrical field (Li et al, , 2013Gao et al, 2010;An et al, 2013;Jin et al, 2020), as well as ULF geomagnetic anomaly (Hu et al, 2009;Wang et al, 2009;Hayakawa et al, 2015;Li et al, 2015;Cheng et al, 2010;Li et al, 2019), before the 12 May 2008 Wenchuan M S 8.0 earthquake have been gradually reported. At the same time, ionospheric variations registered by different equipment of ground-based ionosonde data (Zhao et al, 2008;Sun et al, 2011;Maurya et al, 2013;and references therein), DEMETER satellite data Onishi et al, 2011;Liu et al, 2015;Walker et al, 2013;and references therein),…”

Long‐Term Variations of Energetic Electrons Scattered by Signals From the North West Cape Transmitter

“…In survey mode, electron fluxes with energies from 70 keV to 2.4 MeV are measured by 128 energy channels every 4 s. In burst mode, an electron energy spectrum is obtained with 256 energy channels per second. The burst mode opens when DEMETER satellite passes active seismic regions (An et al., 2011). Note that IDP is switched off at auroral latitudes (invariant latitude >65°, Sauvaud et al., 2006).…”

Preliminary proposal of scientific data verification in CSES mission

“…(Zhu and Wang 2011;Cutler et al 2008;An et al 2011) For the cross-verification, we can compare the scientific data from different payloads in CSES and compare the data from CSES with that from other similar satellites, such as SWARM satellite.…”