Sub-ionospheric very low frequency perturbations associated with the 12 May 2008 &amp;lt;i&amp;gt;M&amp;lt;/i&amp;gt; = 7.9 Wenchuan earthquake

Maurya, Amit Kumar; Singh, Rajesh; Veenadhari, B.; Kumar, Sushil; Singh, Abhay Kumar

doi:10.5194/nhess-13-2331-2013

Cited by 21 publications

(24 citation statements)

References 24 publications

(42 reference statements)

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“…Many researchers have also performed investigations on seismo-ionospheric effects since the occurrence of the Wenchuan M S 8.0 EQ. These studies include at least ionospheric changes of ground-based ionosonde data [57][58][59][60][61][62][63][64], DEMETER satellite data [17,[65][66][67][68][69][70][71][72][73][74][75][76][77][78], ground-based GPS satellite data [17,28,57,58,74,77,[79][80][81][82][83][84], radio occultation data from six microsatellites of FORMOSAT3/COSMIC (F3/C) data [81,84,85], and CHAMP (challenging minisatellite payload) satellite data [77].…”

Section: Spatial Ionospheric Anomaliesmentioning

confidence: 99%

Indications of Ground-based Electromagnetic Observations to A Possible Lithosphere–Atmosphere–Ionosphere Electromagnetic Coupling before the 12 May 2008 Wenchuan MS 8.0 Earthquake

Lü

Zhang

et al. 2019

Atmosphere

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A large number of various precursors have been reported since the Wenchuan M S 8.0 earthquake (EQ) took place on 12 May 2008 in China. In this work, previous investigations of both ground-based electromagnetic (EM) parameters and spatial ionospheric parameters were first examined. The statistical results showed that various anomalies presented different time-scale variations but tended to be characterized by a common feature -reaching their climax on 9 May, three days before the Wenchuan event, which indicates a lithosphere-atmosphere-ionosphere (LAI) electromagnetic coupling. Second, the fluctuations on 9 May based on the observational ground-based ultra low frequency (ULF) electrical field at the Gaobeidian (GBD) station and the direct current/ultra low frequency (DC-ULF) geomagnetic vertical Z field at the Chengdu (CD) station were comparably analyzed with those of ionospheric disturbances reported previously. The results showed that distinct electromagnetic changes, geomagnetic "double low-point" phenomena, and ionospheric disturbances above both sides of the Earth started in turn, respectively, but reached their climax simultaneously within dozens of hours on 9 May. This evolutionary process increases the probability that electromagnetic energy propagates from the epicentral area, via the atmosphere and ionosphere, to the equatorial plane, and through this plane finally to its magnetically conjugated area in the opposite hemisphere, causing electromagnetic disturbances on the Earth's surface, in the atmosphere, and in the ionosphere and its conjugate point, in that order.

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Section: Spatial Ionospheric Anomaliesmentioning

confidence: 99%

Indications of Ground-based Electromagnetic Observations to A Possible Lithosphere–Atmosphere–Ionosphere Electromagnetic Coupling before the 12 May 2008 Wenchuan MS 8.0 Earthquake

Lü

Zhang

et al. 2019

Atmosphere

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“…Maurya et al (2013) reported VLF (very low frequency) sub-ionospheric perturbations before the Wenchuan Earthquake. They identified a significant increase in nighttime amplitude fluctuation and dispersion 2 d prior to the earthquake.…”

Section: M79 Wenchuan Earthquakementioning

confidence: 96%

Recent progress in ionospheric earthquake precursor study in China: A brief review

Liu

2015

Journal of Asian Earth Sciences

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“…Short‐term prediction of their occurrence seems the possible way of their mitigation [ Hayakawa, ]. During the past three decades, utilizing ground, and satellite data, several studies related to pre‐ and post‐earthquake anomalies in the D , E , and F regions of the ionosphere together with the coseismic signatures were carried out in the direction of short time EQ forecast/precursor research [e.g., Hayakawa et al , ; Maurya et al , ; Ondoh and Hayakawa , ; Sunil et al , ]. All these wide varieties of observations are seldom consistent and often yield conflicting results even for the same earthquake.…”

Section: Introductionmentioning

confidence: 99%

The 25 April 2015 Nepal Earthquake: Investigation of precursor in VLF subionospheric signal

Maurya

Venkatesham²,

Tiwari³

et al. 2016

JGR Space Physics

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We present a critical analysis of the observations and interpretation of VLF subionospheric measurements related to the main Nepal Gorkha earthquake which occurred on 25 April 2015 (Mw7.8) and its major aftershock on 12 May 2015 (Mw7.3). The VLF narrowband signal used is from North West Cape (NWC) (19.8 kHz) VLF transmitter located in Australia and recorded at Allahabad (latitude 25.41°N, longitude 81.93°E). Allahabad is located very close (~360 km) to these earthquake epicenters. Two widely used analysis, viz., (1) terminator time and (2) nighttime fluctuation techniques, are applied to extract seismic related effects in the NWC narrowband VLF data. The terminator time analysis yields statistically significant shifts of ~45 and ~26 min, respectively, in evening terminator time in the NWC VLF amplitude signal, 1 day before both the earthquakes. The nighttime fluctuation method shows a consistent, statistically significant, increase in three parameters 1 day before the earthquake. The observed terminator time and nighttime fluctuation shifts were associated with these earthquakes only after scrutinizing possible contributions from other potential sources such as solar activity; other earthquakes on the signal path; and meteorological disturbances such as lightning activity, wind speed, and temperature along the transmitter‐receiver great circle path. The VLF subionospheric signal analysis results unambiguously point toward the presence of seismically excited atmospheric gravity waves during these major earthquakes and their important role in providing the coupling between the seismic source region and overlying ionosphere.

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Sub-ionospheric very low frequency perturbations associated with the 12 May 2008 <i>M</i> = 7.9 Wenchuan earthquake

Abstract: Abstract. The present study reports the VLF (very low frequency) sub-ionospheric perturbations observed on transmitter JJI (22

Cited by 21 publications

References 24 publications

Indications of Ground-based Electromagnetic Observations to A Possible Lithosphere–Atmosphere–Ionosphere Electromagnetic Coupling before the 12 May 2008 Wenchuan MS 8.0 Earthquake

Indications of Ground-based Electromagnetic Observations to A Possible Lithosphere–Atmosphere–Ionosphere Electromagnetic Coupling before the 12 May 2008 Wenchuan MS 8.0 Earthquake

Recent progress in ionospheric earthquake precursor study in China: A brief review

The 25 April 2015 Nepal Earthquake: Investigation of precursor in VLF subionospheric signal

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