Directivity and apparent velocity of the coseismic ionospheric disturbances observed with a dense GPS array

Heki, Kosuke; Ping, Jinsong

doi:10.1016/j.epsl.2005.06.010

Cited by 254 publications

(386 citation statements)

References 17 publications

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“…For those traveling below the mesopause of 90 km altitude, the average AGW speeds are about 300-400 m/s (Liu et al, 2006), while for those departing with relatively high elevation angles and mainly traveling in the ionosphere (or thermosphere) above 100 km altitude, the associated average AGW speeds could be up to 700-1100 m/s (cf. Artru et al, 2004; Heki and Ping, 2005;Liu et al, 2010). Therefore, the speed of 900 m/s suggests the 2 nd STID being related to AGWs mainly traveling in the ionosphere of about 200 km altitude, which is close to the value of 1032-1045 m/s given by Liu et al (2011) and the 1 km/s (1000 m/s) given by Rolland et al (2011).…”

Section: Discussionsupporting

confidence: 70%

Seismo-traveling ionospheric disturbances of ionograms observed during the 2011 M w 9.0 Tohoku Earthquake

Liu

Sun

2011

Earth Planet Sp

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In this paper, sequences of ionograms recorded by 4 ionosondes in Japan and 1 in Taiwan are employed to examine seismo traveling ionospheric disturbances (STIDs) triggered by the 11 March, 2011, M 9.0 Tohoku Earthquake. The circle method, a standard/traditional technique of seismologists for locating an earthquake, is used to find the origin and compute the propagation speed of the triggered STID. Results show that the STID speeds induced by Rayleigh waves, acoustic gravity waves mainly traveling in the ionosphere, and tsunami waves of the Tohoku Earthquake are 2100-3200 m/s (2.1-3.2 km/s), 900 m/s, and 200 m/s (720 km/hr), respectively. The origins derived by the circle method near the epicenter confirm that the observed STIDs were triggered by the seismic waves and tsunami waves of the Tohoku Earthquake.

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Section: Discussionsupporting

confidence: 70%

Seismo-traveling ionospheric disturbances of ionograms observed during the 2011 M w 9.0 Tohoku Earthquake

Liu

Sun

2011

Earth Planet Sp

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“…This ratio is small enough at the F layer height, and the ion moves mainly in the direction of the magnetic field irrespectively of the neutral particle movements. Therefore, the amplitude of the northward waves is smaller than that of the southward ones [Heki and Ping, 2005;Otsuka et al, 2006]. Meanwhile, the other reason might be that the poleward blowing winds in the daytime may play an important role, as the equatorward direction of bow waves follows the theory of directional filtering effect of AGWs.…”

Section: Discussionmentioning

confidence: 99%

Bow and stern waves triggered by the Moon's shadow boat

Liu¹,

Sun

Kakinami

et al. 2011

Geophys. Res. Lett.

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It has been predicted that the Moon's shadow, the cooling region, sweeping over the Earth's atmosphere with a supersonic speed could trigger bow waves since 1970. The longest total solar eclipse within next hundred years occurring on 22 July 2009 sweeps over the Eastern Asia region during the noontime period. An analysis of the Hilbert‐Huang transform (HHT) is applied to study ionospheric TEC (total electron content) derived from ground‐based GPS receivers in Taiwan and Japan. We not only find the feature of the predicted bow wave but also the stern wave on the equator side of the eclipse path, as well as the stern wake right behind the Moon's shadow boat. The bow and stern waves are formed by acoustic gravity waves of periods about 3 and/or 5 minutes traveling equatorward with a phase speed of about 100 m/s in the ionosphere.

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“…In particular, ionospheric signatures of class M = 8 earthquakes were imaged near the source (Heki and Ping, 2005; Copyright c The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences; TERRAPUB.…”

Section: Introductionmentioning

confidence: 99%

The resonant response of the ionosphere imaged after the 2011 off the Pacific coast of Tohoku Earthquake

et al. 2011

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International audienceWe provide here a preliminary analysis of the ionospheric perturbations observed after the 11 March 2011 Tohoku Earthquake using a GPS-derived Total Electron Content (TEC) technique. Such anomalies are routinely observed after seismic events of magnitude M w = 6 and more. Here, we use the high density and the wide coverage of the Japanese Global Positioning System (GPS) network GEONET to image the ionosphere just after the main shock. We describe ionospheric perturbations with exceptional extension in amplitude and duration. As already seen in earlier events, a first intense signal is observed about 10 minutes after the seismic rupture; the first response consists in two modes: one propagating beyond 3 km/s and the other at nearly 1 km/s. A further analysis of TEC time series of the latter mode near the source shows the typical frequencies of acoustic resonance. Beyond 400 km from the source, both the tsunami induced gravity wave and a third mode are imaged, the latter for the first time. We show that the pattern of this slow (225 m/s ± 10 m/s) and long period gravity wave (1.8 ± 0.2 mHz) is most visible in the NorthWest of the epicentral area. This description is corroborated by a computation of the normal modes of the solid Earth-atmosphere system

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Directivity and apparent velocity of the coseismic ionospheric disturbances observed with a dense GPS array

Cited by 254 publications

References 17 publications

Seismo-traveling ionospheric disturbances of ionograms observed during the 2011 M w 9.0 Tohoku Earthquake

Seismo-traveling ionospheric disturbances of ionograms observed during the 2011 M w 9.0 Tohoku Earthquake

Bow and stern waves triggered by the Moon's shadow boat

The resonant response of the ionosphere imaged after the 2011 off the Pacific coast of Tohoku Earthquake

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