A statistical study of ionospheric earthquake precursors monitored by using equatorial ionization anomaly of GPS TEC in Taiwan during 2001–2007

Liu, J. Y.; Chen, Chia-Hung; Chen, Y. I.; Yang, Wen-Hsi; Oyama, K.‐I.; Kuo, Kai-Wen

doi:10.1016/j.jseaes.2010.02.012

Cited by 84 publications

(49 citation statements)

References 16 publications

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“…A detailed understanding of ionospheric variability and coupling mechanisms is also necessary for the challenging task to correctly recognize/identify potential ionospheric precursors of earthquakes. In this case, if such precursors exist, the coupling between the solid Earth, troposphere, upper atmosphere, and ionosphere is, however, claimed to be based on changes in electric field or changes of global electric circuit owing to radon escape rather than on acoustic gravity waves [Harrison et al 2010;Liu et al 2010;Pulinets and Davidenko 2014].…”

Section: Introductionmentioning

confidence: 99%

Ionospheric signatures of the April 25, 2015 Nepal earthquake and the relative role of compression and advection for Doppler sounding of infrasound in the ionosphere

Chum

Liu

Laštovička

et al. 2016

Earth Planets Space

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Ionospheric signatures possibly induced by the Nepal earthquake are investigated far outside the epicentral region in Taiwan (~3700 km distance from the epicenter) and in the Czech Republic (~6300 km distance from the epicenter). It is shown that the ionospheric disturbances were caused by long period,~20 s, infrasound waves that were excited locally by vertical component of the ground surface motion and propagated nearly vertically to the ionosphere. The infrasound waves are heavily damped at the heights of F layer at around 200 km, so their amplitude strongly depends on the altitude of observation. In addition, in the case of continuous Doppler sounding, the value of the Doppler shift depends not only on the advection (up and down motion) of the reflecting layer but also on the compression/ rarefaction of the electron gas and hence on the electron density gradient. Consequently, under significant differences of reflection height of sounding radio waves and partly also under large differences in plasma density gradients, the observed ionospheric response at larger distances from the epicenter can be comparable with the ionospheric response observed at shorter distances, although the amplitudes of causative seismic motions differ by more than one order of magnitude.

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Section: Introductionmentioning

confidence: 99%

Ionospheric signatures of the April 25, 2015 Nepal earthquake and the relative role of compression and advection for Doppler sounding of infrasound in the ionosphere

Chum

Liu

Laštovička

et al. 2016

Earth Planets Space

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“…Liu et al (2001) pioneer using the TEC derived from a local network of ground-based GPS receivers to detect SIPs appearing 1, 3, and 4 days before the 21 September 1999 M7.6 Chi-Chi earthquake. Many event studies and statistical analyses on SIPs of the GPS TEC related to large earthquakes in Taiwan have been carried out Kamogawa et al 2004;Liu et al 2004aLiu et al , b, 2006Liu et al , 2008Liu et al , 2010aTsai et al 2004;Saroso et al 2008;Nishihashi et al 2009). Following that, the global ionosphere map of the GPS TEC has been used to globally study SIPs appearing few days before the 26 December 2004 M9.3 SumatraAndaman Earthquake (Liu et al 2010b), the 11 May 2008 M8.0 Wenchuan earthquake (Liu et al , 2015, and the 12 January 2010 M7.0 Haiti earthquake (Liu et al 2011).…”

Section: Examples Using Rocsat-1/ipeimentioning

confidence: 99%

Advanced Ionospheric Probe scientific mission onboard FORMOSAT-5 satellite

Lin¹,

Chao²,

Liu³

et al. 2017

Terr. Atmos. Ocean. Sci.

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Advanced Ionospheric Probe (AIP) is a piggyback science payload developed by National Central University for FORMOSAT-5 satellite to explore space weather/ climate and seismic precursors associated with strong earthquakes. The AIP is an all-in-one plasma sensor that measures ionospheric plasma concentrations, velocities, and temperatures in a time-sharing way and is capable of measuring ionospheric plasma irregularities at a sample rate up to 8192 Hz over a wide range of spatial scales. Electroformed gold grids used in the AIP in theory construct planar electric potential surfaces better than woven grids. Moreover, a plasma injection test performed in the Space Plasma Simulation Chamber has verified that no significant hysteresis is found in current-voltage curves measured by the AIP. It indicates that the AIP can make an accurate measurement of the ionospheric plasma parameters in space. Finally, Ionospheric Plasma and Electrodynamics Instrument (IPEI) observations onboard the ROCSAT-1 satellite are applied to show that the scientific objectives of ionospheric space weather/climate and seismo-ionospheric precursors (SIPs) of the FORMOSAT-5/AIP can be fulfilled. The observations reveal that ion parameter global distributions are helpful in studying the formation and variation in temperature crests and troughs in the 2200 -2300 local time sector, as well as SIPs in the density and the velocity over the epicenter area, which are anticipated for the FORMOSAT-5 satellite orbit.

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“…The equatorial anomaly is the effect of a dynamo eastward electric field generated by the atmospheric tides near the magnetic equator where the magnetic field is horizontal [31]. Generally, the equatorial anomaly appears in the morning, reaches its greatest development in the post noon and then gradually disappears.…”

Section: Equatorial Anomaly Dynamicsmentioning

confidence: 99%

Analysis of Ionospheric Vertical Total Electron Content before the 2014 Mw8.2 Chile Earthquake

Jiang¹,

Ma²,

Zhou³

et al. 2017

Preprint

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This paper studies ionospheric vertical total electron content (VTEC) variations before the 2014 Mw8.2 Chile earthquake. VTEC derived from 14 GPS (Global Positioning System) stations and GIM (Global Ionospheric Map) were used to analyze ionospheric variations before the earthquake using the sliding interquartile range method, and results showed that significant positive VTEC anomalies occurred on 28 March. To explore possible causes of these anomalies, effects of solar and geomagnetic activities were examined, and VTEC variations during 17 March to 31 March in 2009-2013 were cross-compared. Also, VTEC for a full year before the earthquake was investigated. Results indicated that these anomalies were weakly associated with high solar activities and geomagnetic storms and that these anomalies were not normal seasonal and diurnal variations. An analysis of the spatial distribution of the observed anomalies was also presented, and it demonstrated that anomalies specifically appeared around the epicenter on 28 March. It suggests that observed anomalies may be associated with the subsequent Chile earthquake. Equatorial anomaly variations were analyzed to discuss the possible physical mechanism, and results showed that the equatorial anomaly unusually increased on 28 March, which indicates that anomalous electric fields generated in the earthquake preparation area and the meridional wind are possible causes of the observed ionospheric anomalies.

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A statistical study of ionospheric earthquake precursors monitored by using equatorial ionization anomaly of GPS TEC in Taiwan during 2001–2007

Cited by 84 publications

References 16 publications

Ionospheric signatures of the April 25, 2015 Nepal earthquake and the relative role of compression and advection for Doppler sounding of infrasound in the ionosphere

Ionospheric signatures of the April 25, 2015 Nepal earthquake and the relative role of compression and advection for Doppler sounding of infrasound in the ionosphere

Advanced Ionospheric Probe scientific mission onboard FORMOSAT-5 satellite

Analysis of Ionospheric Vertical Total Electron Content before the 2014 Mw8.2 Chile Earthquake

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