VLF radio wave anomalies associated with the 2010 Ms 7.1 Yushu earthquake

Shen, Xuhui; Zhima, Zeren; Zhao, Shufan; Geng, Qian; Ye, Qing; Ruzhin, Yu. Ya.

doi:10.1016/j.asr.2017.02.040

Cited by 16 publications

(9 citation statements)

References 24 publications

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“…VLF/HF radio waves emitted by ground‐based transmitters provide us a good way to test the capability of in‐flight instruments, for the VLF/HF radio waves propagate in the wave guide of lithosphere–ionosphere. Under certain conditions the radio waves can penetrate through the sub‐ionospheric layer, propagating up to the satellite's orbit, and can be recorded by satellites (Shen XH et al, ). We chose some active ground based VLF/HF transmitters to check the EFD's capabilities.…”

Section: First Results and Preliminary Analysismentioning

confidence: 99%

The Electric Field Detector (EFD) onboard the ZH-1 satellite and first observational results

Huang

Lei

et al. 2018

Earth and Planetary Physics

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Previous studies have reported that, before or after occurrences of strong earthquakes, some low earth orbit satellites recorded ionospheric disturbances, including electromagnetic emissions and plasma fluctuations over the epicenter region or its conjugate point. Theoretically speaking, due to some electromagnetic coupling effect, electromagnetic emissions from the earthquake preparation zone could propagate from the lithosphere to the atmosphere, and could reach the ionosphere, even up to the inner magnetosphere. This paper introduces the electric field detector (EFD) onboard the ZhangHeng‐1 satellite (ZH‐1). The EFD is designed to measure electric field fluctuations within the broad frequency range of DC to 3.5 MHz, divided into 4 channels: ULF (DC–16 Hz), ELF (6 Hz–2.2 kHz), VLF (1.8 kHz–20 kHz) and HF (18 kHz–3.5 MHz). The sampling rates of the channels are 125 Hz, 5 kHz, 50 kHz and 10 MHz, respectively. The EFD includes 4 spherical probes mounted on a over 4.5 m boom and an electronic box inside the satellite module. The resolution of the EFD is 1 μV·m‐1·Hz‐1/2 at frequencies from DC to 16 Hz, and the sensitivity is 0.1 μV·m‐1·Hz‐1/2 at frequencies from 6 Hz to 2.2 kHz, 0.05 μV·m‐1·Hz‐1/2 in the band 1.8 kHz to 20 kHz, and 0.1μV·m‐1·Hz‐1/2 from 20 kHz to 3.5 MHz. The dynamic range from DC to 20 kHz is over 120 dB, and over 96 dB from 20 kHz to 3.5 MHz. The EFD has two observation modes: survey mode and burst mode. The survey mode concentrates primarily on electric field power density values; the burst mode provides high sampling rate waveform data. The detailed configuration of the EFD onboard the ZH‐1 is also introduced in this paper. During the six months’ orbit test phase, the EFD recorded a number of natural electromagnetic emissions. Preliminary analysis of these data suggests that the EFD performs well onboard the ZH‐1 and is meeting the requirements of the scientific objectives of ZH‐1.

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Section: First Results and Preliminary Analysismentioning

confidence: 99%

The Electric Field Detector (EFD) onboard the ZH-1 satellite and first observational results

Huang

Lei

et al. 2018

Earth and Planetary Physics

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“…VLF radio waves are mainly used as longdistance communication and navigation in the lithosphereionosphere waveguide, however, some portions of VLF radio wave energies leak into the ionosphere, propagating upward and reaching to satellite altitudes. The satellite recorded VLF radio waves usually appear at frequencies over 10 kHz to even to 30 kHz (Zhao et al, 2019), the spectra of VLF radio waves recorded by satellite usually exhibit a narrow transversal spectrum peak at the central frequency of the emitted radio waves (Shen et al, 2017;Zhang et al, 2018). Additionally, no VLF transmitter is reported near Sumatra area.…”

Section: Discussionmentioning

confidence: 99%

“…For convenience, considering the projection feature of satellite orbit on the ground, we chose a square area of around 1,800 km at satellite's altitude, that is the epicenter (2.4°N, 97.1°E) ± 8°area, or (5.6°S-10.4°N, 89°E−105°E). We then extracted the PSD values at frequency (300-800 Hz) over the studied area from each revisiting orbit of the above five orbits, and re-sorted them as five sets of time-series data, and then we applied a running quartile method (Zhima et al, 2012b;Liu et al, 2013;Shen et al, 2017) to examine the long-term trend, as shown in Figure 4. The running medians, along with the inter-quartile ranges (IQR, being equal to the difference between the third and first quartiles) were computed by using the three previous and three successive orbits of the current orbit (7 orbits in total).…”

Section: Revisiting Orbitsmentioning

confidence: 99%

The Seismic Electromagnetic Emissions During the 2010 Mw 7.8 Northern Sumatra Earthquake Revealed by DEMETER Satellite

Zhima¹,

Piersanti

et al. 2020

Front. Earth Sci.

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“…Shen XH et al (2017) conducted a comparative study on propagation of VLF radio signals before strong earthquakes, based on ground‐based and space‐based observations. The ground observations of VLF radio signals show that the disturbance intensity of VLF waves' amplitudes relative to the background gets an enhancement, one day before the 2010 M s 7.1 Yushu earthquake, of more than 22% at 11.9 kHz, 27% at 12.6 kHz, and 62% at 14.9 kHz along the path from Novosibirsk‐TH.…”

Section: Ionospheric Dynamicsmentioning

confidence: 99%

Chinese ionospheric investigations in 2016–2017

Liu

Wan

2018

Earth and Planetary Physics

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After the release of the previous report to the Committee on Space Research (COSPAR) on progress achieved by Chinese scientists in ionospheric researches (Liu LB and Wan WX, 2016), in the recent two years (2016–2017) many interesting new investigations into various ionospheric related issues have been completed. In this report, about 100 publications are summarized. The topics highlighted are as follows: Ionospheric space weather, ionospheric dynamics, ionospheric climatology and modelling, ionospheric irregularity and scintillation, Global Navigation Satellite System (GNSS) related ionospheric issues and other techniques, and radio wave propagation in the ionosphere. An outstanding feature is that more and more observations from the Meridional Project supported the ionospheric investigations.

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VLF radio wave anomalies associated with the 2010 Ms 7.1 Yushu earthquake

Cited by 16 publications

References 24 publications

The Electric Field Detector (EFD) onboard the ZH-1 satellite and first observational results

The Electric Field Detector (EFD) onboard the ZH-1 satellite and first observational results

The Seismic Electromagnetic Emissions During the 2010 Mw 7.8 Northern Sumatra Earthquake Revealed by DEMETER Satellite

Chinese ionospheric investigations in 2016–2017

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