Ionospheric disturbances (infrasound waves) over the Czech Republic excited by the 2011 Tohoku earthquake

Chum, Jaroslav; Hruška, František; Zedník, Jan; Laštovička, Jan

doi:10.1029/2012ja017767

Cited by 72 publications

(134 citation statements)

References 43 publications

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“…The wind field associated with the seismic infrasound at ionospheric altitude transports the ionospheric plasma parallel to the magnetic field and creates perturbations whose features correlate well with that of the infrasound. Recently, Chum et al (2012) found that the features of seismic wave packets observed on the ground using the seismometer matched exactly with the features of the ionospheric response observed using Doppler sounding. The periodicities of the ionospheric perturbations were found to be exactly similar to the Rayleigh wave periodicities.…”

Section: Introductionmentioning

confidence: 76%

“…Chum et al (2012) have also described the infrasound amplification and attenuation in details. The methodology utilized by Chum et al (2012) has been adopted in this study to determine the infrasound amplification and attenuation in the atmosphere. The modelled amplification and attenuation of the infrasound (0.08 Hz) at different height levels with respect to the forcing on the ground is presented next.…”

Section: Propagation Of Seismic Infrasound In the Atmospherementioning

confidence: 99%

“…The main relaxation losses are the classical and rotational losses (Sutherland and Bass, 2004;Bass et al, 1984). Chum et al (2012) have also described the infrasound amplification and attenuation in details. The methodology utilized by Chum et al (2012) has been adopted in this study to determine the infrasound amplification and attenuation in the atmosphere.…”

Section: Propagation Of Seismic Infrasound In the Atmospherementioning

confidence: 99%

“…On the other hand, many investigations have reported the ionospheric perturbations to remain confined to the bottom of the F layer (e.g. Chum et al, 2012;Maruyama et al, 2016). Likewise, different researchers have proposed different modes of acoustic propagation.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Simulating the dependence of seismo-ionospheric coupling on the magnetic field inclination

et al. 2018

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Abstract. Infrasound generated during a seismic event upon reaching the ionospheric heights possesses the ability to perturb the ionosphere. Detailed modelling investigation considering 1-D dissipative linear dynamics, however, indicates that the magnitude of ionospheric perturbation strongly depends on the magnetic field inclination. Physics-based SAMI2 model codes have been utilized to simulate the ionosphere perturbations that are generated due to the action of the vertical wind perturbations associated with the seismic infrasound. The propagation of the seismic energy and the vertical wind perturbations associated with the infrasound in the model has been considered to be symmetric about the epicentre in the north-south directions. Ionospheric response to the infrasound wind, however, has been highly asymmetric in the model simulation in the north-south directions. This strong asymmetry is related to the variation in the inclination of the Earth's magnetic field north and south of the epicentre. Ionospheric monitoring generally provides an efficient tool to infer the crustal propagation of the seismic energy. However, the results presented in this paper indicate that the mapping between the crustal process and the ionospheric response is not a linear one. These results also imply that the lithospheric behaviour during a seismic event over a wide zone in low latitudes can be estimated through ionospheric imaging only after factoring in the magnetic field geometry.Keywords. Atmospheric composition and structure (pressure density and temperature) -history of geophysics (atmospheric sciences) -ionosphere (ionosphere-atmosphere interactions)

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Section: Introductionmentioning

confidence: 76%

Section: Propagation Of Seismic Infrasound In the Atmospherementioning

confidence: 99%

Section: Propagation Of Seismic Infrasound In the Atmospherementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Simulating the dependence of seismo-ionospheric coupling on the magnetic field inclination

et al. 2018

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“…The dominant seismic wave energy at remote distances is associated with the short-period Airy phase of Rayleigh waves with a period of 10 to 50 s (Oliver, 1962), which propagates over long distances with little dissipation compared to other wave modes. As the excited infrasound signals propagate upward, their amplitudes increase due to the conservation of momentum in the density-rarefied atmosphere (e.g., Chum et al, 2012;Maruyama and Shinagawa, 2014). Infrasound signals with periods longer than ∼ 15 s reach ionospheric altitudes (Tanaka et al, 1984) and interact with ions through neutralion collisions.…”

Section: Introductionmentioning

confidence: 99%

Interpretation of deformed ionograms induced by vertical ground motion of seismic Rayleigh waves and infrasound in the thermosphere

2016

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Abstract. The vertical ground motion of seismic surface waves launches acoustic waves into the atmosphere and induces ionospheric disturbances. Disturbances due to Rayleigh waves near the short-period Airy phase appear as wavy fluctuations in the virtual height of an ionogram and have a multiple-cusp signature (MCS) when the fluctuation amplitude is increased. An extremely developed MCS was observed at Kazan, Russia, after the 2010 M 8.8 Chile earthquake. The ionogram exhibited steep satellite traces for which the virtual heights increased rapidly with frequency starting near the top of cusps and continuing for 0.1-0.2 MHz. This complicated ionogram was analyzed by applying a ray tracing technique to the radio wave propagation in the ionosphere that was perturbed by acoustic waves. Acoustic wavefronts were inclined by the effects of finite Rayleigh wave velocity and sound speed in the thermosphere. The satellite echo traces were reproduced by oblique returns from the inclined wavefronts, in addition to the nearly vertical returns that are responsible for the main trace.

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Infrasonic sounds excited by seismic waves of the 2011 Tohoku‐oki earthquake as visualized in ionograms

Maruyama

Shinagawa

2014

JGR Space Physics

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After the M 9.0 Tohoku‐oki earthquake in 2011, strong deformation of ionogram echo traces, forming multiple cusp signatures (MCSs), were observed at three stations 790–1880 km from the epicenter. The vertical structure of the ionospheric disturbances was determined by true height analysis and compared with broadband seismograph records at stations close to the ionosondes. These ionospheric disturbances were caused by vertically propagating acoustic waves excited by the up/down ground motion of seismic waves. Numerical simulations have shown that acoustic waves with a period of 15–40 s and amplitude of order 1 mm/s at the ground level were sufficient to create MCSs as sharp as those observed. These acoustic wave parameters are consistent with the seismic records if the motion of the air mass on the ground level is assumed to be the same as the ground motion. The travel time diagram of the seismic records along the line connecting the epicenter and ionosondes showed that the first MCS ionogram detected at each station was caused by P waves, while the others were caused by Rayleigh waves.

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Ionospheric disturbances (infrasound waves) over the Czech Republic excited by the 2011 Tohoku earthquake

Cited by 72 publications

References 43 publications

Simulating the dependence of seismo-ionospheric coupling on the magnetic field inclination

Simulating the dependence of seismo-ionospheric coupling on the magnetic field inclination

Interpretation of deformed ionograms induced by vertical ground motion of seismic Rayleigh waves and infrasound in the thermosphere

Infrasonic sounds excited by seismic waves of the 2011 Tohoku‐oki earthquake as visualized in ionograms

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