Statistical analyses on the ionospheric total electron content related to M ≥ 6.0 earthquakes in China during 1998 - 2015

Liu, Chengyan; Liu, Jann Yenq; Chen, Yuh Ing; Qin, Fei; Chen, Wei Sheng; Yan, Xia; Bai, Z. Q.

doi:10.3319/tao.2018.03.11.01

Cited by 17 publications

(73 citation statements)

References 21 publications

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“…September, its polarity (positively anomalous) agrees with statistical results of the pre-EQ TEC anomalies over Japan [Kon et al, 2011;Liu et al, 2013]. However, we are afraid that this is also a geomagnetic effect, because this kind of positive anomaly appears almost everywhere around the world, though the Dst index is about -20 nT, only a small disturbance.…”

Section: Upper Ionospheric Perturbation As Detected By Tec Datasupporting

confidence: 79%

On electromagnetic precursors to the Hokkaido earthquake in September, 2018 and consideration of lithosphere-atmosphere-ionosphere coupling

Hayakawa¹,

Рожной²,

Solovieva³

et al. 2019

IJEAR

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Electromagnetic precursors have been investigated for a recent relatively large earthquake (EQ) with magnitude M=6.7 occurred in the Hokkaido Island, Japan on 5 September (UT), 2018 on the basis of coordinated data on the lower ionospheric perturbation with subionospheric VLF/LF propagation anomalies monitored in Japan and in Russia, on the upper F region anomaly with GIM (global ionosphere map) TEC (Total Electron Content) and on the stratospheric behavior with the use of ERA5 temperature profile data. It is found that there were observed the clearest VLF/LF propagation anomalies indicative of seismogenic lower ionospheric perturbations above the EQ epicenter on 4 and 5 September before the EQ and 6 September even after it because this period was geomagnetically quiet. As for the F region, an anomaly in TEC over the EQ epicenter appeared only on 5 September, but it is quite uncertain whether this anomaly is related to either a pre-EQ effect or a geomagnetic storm effect. Then, we have tried to find if there were some seismo-related AGW (atmospheric gravity wave) activities in the stratosphere, but though we have found a lot of anomalies, they are highly likely to be associated with the activities by convective weather systems. Even though we have recently identified the first convincing direct evidence on the Atmospheric oscillation hypothesis in the lithosphere-atmosphere-ionosphere coupling (LAIC) mechanism for the 2016 Kumamoto EQ [Yang et al., 2019], this paper aimed initially to obtain further evidence on this channel. However, the above experimental findings may provide a negative result in this direction; that is, this Atmospheric oscillation channel is unlikely to be in operation for the present 2018 Hokkaido EQ, suggesting other channels in the LAIC effect. So we have made extensive discussions on this LAIC mechanism for this Hokkaido EQ with special reference to the 2016 Kumamoto EQ and the 2011 Tohoku EQ.

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Section: Upper Ionospheric Perturbation As Detected By Tec Datasupporting

confidence: 79%

On electromagnetic precursors to the Hokkaido earthquake in September, 2018 and consideration of lithosphere-atmosphere-ionosphere coupling

Hayakawa¹,

Рожной²,

Solovieva³

et al. 2019

IJEAR

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“…Other ionospheric parameters usually change several days before earthquakes. For example, the statistical studies have reported that ion density perturbations occur 5 days before (Yan et al, 2017); total electron content significantly decrease 2–9 days before (Liu et al, 2013), and abnormal decrease of the ionospheric foF2 occurs within 5 days before the earthquakes (Liu et al, 2006). Our statistical results indicate that the time scale of pre‐earthquake ULF disturbances in the ionosphere is similar to other ionospheric parameters.…”

Section: Discussionmentioning

confidence: 99%

“…Several case studies suggest that anomalous ULF wave activity before earthquakes is recorded by satellites in the ionosphere, such as the Swarm and the DEMETER satellites (De Santis et al, 2017; Walker et al, 2013). On the other hand, it is now well established that other ionospheric parameters, for instance, electron/ion density, total electron content, and ELF/VLF wave intensity, have shown pre‐earthquake effects (e.g., Liu et al, 2013; Němec et al, 2008; Yan et al, 2017). However, previous studies have not dealt with the statistical relationship between ULF wave activity in the ionosphere and earthquakes.…”

Section: Introductionmentioning

confidence: 99%

ULF Wave Activity Observed in the Nighttime Ionosphere Above and Some Hours Before Strong Earthquakes

2020

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We examine the relationship between earthquakes and ultralow frequency (ULF) wave activity in the nighttime ionosphere based on the electric field data in the direct current/ULF range observed by the DEMETER satellite over a~5.5 year period from May 2005 to November 2010. ULF wave activity is identified by an automatic detection algorithm and those which occur on the geomagnetic disturbed days (Kp > 3 at any time intervals) are discarded. Only the earthquakes with depth ≤70 km and occurring in the region of |MLat| < 40°are selected. A superposed epoch analysis is performed to study the statistical association between ULF wave activity and the selected earthquakes. The results show that (1) there are clearly temporal and spatial correlations between ULF wave activity and earthquakes whose catalog magnitudes are both ≥4.8 and ≥5.0, and (2) enhanced ULF wave occurrence rate happens~1 day and 1 week before the earthquakes and at less than 200 km distance from the epicenters.

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“…The NT analysis could be applied to any discrete time series with fixed (or not fixed) time spacing. However, we did not need to perform the NT analysis with the 30 s data, because the pre-seismic processes related to the LAIC usually had a much longer time scale of a day to a few weeks (e.g., [ 3 , 5 , 9 ]).…”

Section: Datamentioning

confidence: 99%

“…The ionospheric perturbations mainly appear in two ways. One way is the variations in the F-region electron density and is further seen in the total electron content (TEC) (e.g., [ 3 , 4 , 5 , 6 ]). The other way is the fluctuations in the bottom ionosphere observed using very low-frequency (VLF) and low-frequency (LF) radio wave techniques.…”

Section: Introductionmentioning

confidence: 99%

Natural Time Analysis of Global Navigation Satellite System Surface Deformation: The Case of the 2016 Kumamoto Earthquakes

Yang

Potirakis

Sasmal

et al. 2020

Entropy

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In order to have further evidence of the atmospheric oscillation channel of the lithosphere-atmosphere-ionosphere coupling (LAIC), we have studied criticality in global navigation satellite system (GNSS) surface deformation as a possible agent for exciting atmospheric gravity waves (AGWs) in the atmosphere and GNSS fluctuations in the frequency range of AGWs with the use of the natural time (NT) method. The target earthquake (EQ) is the 2016 Kumamoto EQ with its main shock on 15 April 2016 (M = 7.3, universal time). As the result of the application of the NT method to GNSS data, we found that for the one-day sampled GNSS deformation data and its fluctuations in two AGW bands of 20–100 and 100–300 min, we could detect a criticality in the period of 1–14 April, which was one day to two weeks before the EQ. These dates of criticalities are likely to overlap with the time periods of previous results on clear AGW activity in the stratosphere and on the lower ionospheric perturbation. Hence, we suggest that the surface deformation could be a possible candidate for exciting those AGWs in the stratosphere, leading to the lower ionospheric perturbation, which lends further support to the AGW hypothesis of the LAIC process.

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Statistical analyses on the ionospheric total electron content related to M ≥ 6.0 earthquakes in China during 1998 - 2015

Cited by 17 publications

References 21 publications

On electromagnetic precursors to the Hokkaido earthquake in September, 2018 and consideration of lithosphere-atmosphere-ionosphere coupling

On electromagnetic precursors to the Hokkaido earthquake in September, 2018 and consideration of lithosphere-atmosphere-ionosphere coupling

ULF Wave Activity Observed in the Nighttime Ionosphere Above and Some Hours Before Strong Earthquakes

Natural Time Analysis of Global Navigation Satellite System Surface Deformation: The Case of the 2016 Kumamoto Earthquakes

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