Dependence of near field co-seismic ionospheric perturbations on surface deformations: A case study based on the April, 25 2015 Gorkha Nepal earthquake

Sunil, A. S.; Bagiya, Mala S.; Catherine, J. K.; Rolland, Lucie; Sharma, Nitin; Sunil, P. S.; Ramesh, D. S.

doi:10.1016/j.asr.2016.11.041

Cited by 22 publications

(51 citation statements)

References 26 publications

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“…The disposition of CIP is normally explained invoking surface displacements either at the epicenter or along the rupture as their source (e.g., Astafyeva & Heki, ; Heki et al, ; Rolland et al, ; Sunil et al, , ). However, the Kaikoura earthquake rupture constitutes contributions from two thrust zones of CCTZ and KCTZ; the total rupture duration of ~100 s (Zhang et al, ) is lower than the characteristic period of acoustic waves (~4 min) in upper atmosphere.…”

Section: Discussionmentioning

confidence: 99%

“…The crustal surface deformation associated with the rupture propagation is considered to be the main energy source that induced ionospheric perturbations (e.g., Heki et al, ; Sunil et al, , and references therein). The coseismic surface uplift induces acoustic wave velocity perturbations in the nearby atmosphere, which propagate vertically upward in the region of decreasing neutral density, and thus, their amplitudes increase to conserve the total kinetic energy.…”

Section: Introductionmentioning

confidence: 99%

“…The CIP amplitudes and phase are mainly controlled by the nontectonic forcing mechanisms of geomagnetic field‐wave coupling, satellite geometry at the sounding heights, and ambient ionization density. The azimuthal distribution of near‐field CIP, in general, follows rupture propagation if nontectonic forcing mechanisms favor the evolution of the same (e.g., Bagiya et al, ; Rolland et al, ; Sunil et al, ).…”

Section: Introductionmentioning

confidence: 99%

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Coseismic Contortion and Coupled Nocturnal Ionospheric Perturbations During 2016 Kaikoura, M_w 7.8 New Zealand Earthquake

Bagiya¹,

Sunil²,

Sunil³

et al. 2018

JGR Space Physics

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The oblique‐thrust Kaikoura earthquake of Mw 7.8 that struck New Zealand on 13 November 2016 at 11:02:56 UTC (local time at 00:02:56 a.m. on 14 November 2016) was one of the most geometrically and tectonically complex earthquakes recorded onshore in modern seismology. The event ruptured in the region of multisegmented faults and propagated unilaterally northeastward for more than 170 km from the epicenter. The GPS derived coseismic surface displacements reveal a larger widespread horizontal and vertical coseismic surface offsets of ~6 m and ~2 m, respectively, with two distinct tectonic thrust zones. We study the characteristics of coseismic ionospheric perturbations based on tectonic and nontectonic forcing mechanisms and demonstrate that these perturbations are linked to two distinct surface thrust zones with rotating horizontal reinforcement trending the rupture, rather than merely to the displacements oriented along the rupture propagation direction.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Coseismic Contortion and Coupled Nocturnal Ionospheric Perturbations During 2016 Kaikoura, M_w 7.8 New Zealand Earthquake

Bagiya¹,

Sunil²,

Sunil³

et al. 2018

JGR Space Physics

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“…Recent studies have made early reports on the coseismic ionospheric disturbances observed from ground-based GPS receivers (Reddy & Seemala, 2015;Catherine et al, 2016;Sunil et al, 2017;Chen et al, 2016) and satellite observations (Sun et al, 2016) during this Nepal Gorkha earthquake over Indian subcontinent region. Reddy and Seemala (2015) have studied coseismic ionospheric TEC perturbations and reported that the induced TEC perturbations are due to two modes, namely, shock acoustic wave and surface Rayleigh wave-induced perturbations.…”

Section: Introductionmentioning

confidence: 99%

Coseismic Traveling Ionospheric Disturbances during the M_w 7.8 Gorkha, Nepal, Earthquake on 25 April 2015 From Ground and Spaceborne Observations

et al. 2017

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Coseismic traveling ionospheric disturbances (CTIDs) and their propagation characteristics during Mw 7.8 Gorkha earthquake in Nepal on 25 April 2015 have been investigated using a suite of ground‐based GPS receivers and broadband seismometers along with the spaceborne radio occultation observations over the Indian subcontinent region. Depletion in vertical total electron content, a so called ionospheric hole, is observed near the epicenter ~9–11 min after the onset of earthquake. A positive pulse preceding the depletion, similar to N‐shaped perturbation, propagating with an apparent velocity of ~2.4 km/s is observed on the south. Further, the CTIDs in the southward direction are found to split in to fast (~2.4–1.7 km/s) and slow (~680–520 m/s) propagating modes at epicentral distances greater than ~800 km. However, the velocities of fast mode CTIDs are significantly smaller than the surface Rayleigh wave velocity (~3.7 km/s), indicating that they are not the true imprint of Rayleigh wave, instead, can probably be attributed to the superimposed wave front formed by the mixture of acoustic waves excited by main shock and propagating Rayleigh wave. The southward CTIDs are found to propagate at F2 region altitudes of ~300–440 km captured by Constellation Observing System for Meteorology, Ionosphere and Climate radio occultation observations. The CTIDs with periods of ~4–6 min are observed in all directions with significantly larger amplitudes and faster propagation velocities in south and east directions. The observed azimuthal asymmetry in the amplitudes and velocities of CTIDs are discussed in terms of the alignment with geomagnetic field and nature of surface crustal deformation during the earthquake.

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“…The neutral atmospheric waves which are propagated to ionospheric altitudes interact with ionized medium through collisions which produces density oscillations in the medium. Sunil et al (2017), on the other hand, suggested that one of the reasons for this asymmetry could be due to coupling of earth's magnetic field with the acoustic wave. These waves become more pronounced when they propagate far distances.…”

Section: Introductionmentioning

confidence: 99%

On the Co‐Seismic Ionospheric Disturbances (CIDs) in the Rapid Run Ionosonde Observations Over Allahabad Following M_w 7.8 Nepal Earthquake on April 25, 2015

Sripathi

Singh

Tiwari³

et al. 2020

JGR Space Physics

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We present high-resolution ionosonde observations at Allahabad (25.43°N, 81.84°E) near anomaly crest location in India along with GPS TEC to investigate the possible signatures of co-seismic disturbances (CIDs) in the ionosphere during M w 7.8 Nepal Earthquake that occurred at 06:11:26 UT on 25 April 2015. The epicenter of the earthquake (28.147°N, 84.708°E) was located at~77 km north-west of Kathmandu with a shallow depth of 15 km. The mechanical shock disturbances produce Rayleigh waves and Rayleigh wave induced acoustic gravity waves (AGWs) during earthquake which propagate into the ionosphere and produced plasma density fluctuations due to collisions. The manifestation of these waves produces 'wiggles' or 'cusps' in the ionograms known as Multiple-Cusp Signatures (MCS). The detection of multiple cusps in the ionograms at Allahabad indicates the altitude structure of Rayleigh wave and it's induced AGWs. To confirm co-seismic signatures in ionosonde further, we scaled the ionograms at isodensity and iso-heights along with foF2 (MHz) and h'F (km). The periodogram and wavelet analysis suggest the presence of acoustic gravity waves and gravity waves with frequencies in the range of 0.7-1.5 mHz over the altitude range of 180-250 km. The foF2 variations show wave like oscillations having frequency of 0.5 mHz after the onset of earthquake. The GPS TEC also show signatures of co-seismic perturbations having frequencies in the range of 2-4 mHz and are propagated to southward with a speed of 0.5-1.0 km/s. These results suggest that there exists a good coupling between seismic activity and ionized density perturbations after Nepal earthquake.

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Dependence of near field co-seismic ionospheric perturbations on surface deformations: A case study based on the April, 25 2015 Gorkha Nepal earthquake

Cited by 22 publications

References 26 publications

Coseismic Contortion and Coupled Nocturnal Ionospheric Perturbations During 2016 Kaikoura, M_w 7.8 New Zealand Earthquake

Coseismic Contortion and Coupled Nocturnal Ionospheric Perturbations During 2016 Kaikoura, M_w 7.8 New Zealand Earthquake

Coseismic Traveling Ionospheric Disturbances during the M_w 7.8 Gorkha, Nepal, Earthquake on 25 April 2015 From Ground and Spaceborne Observations

On the Co‐Seismic Ionospheric Disturbances (CIDs) in the Rapid Run Ionosonde Observations Over Allahabad Following M_w 7.8 Nepal Earthquake on April 25, 2015

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Dependence of near field co-seismic ionospheric perturbations on surface deformations: A case study based on the April, 25 2015 Gorkha Nepal earthquake

Cited by 22 publications

References 26 publications

Coseismic Contortion and Coupled Nocturnal Ionospheric Perturbations During 2016 Kaikoura, Mw 7.8 New Zealand Earthquake

Coseismic Contortion and Coupled Nocturnal Ionospheric Perturbations During 2016 Kaikoura, Mw 7.8 New Zealand Earthquake

Coseismic Traveling Ionospheric Disturbances during the Mw 7.8 Gorkha, Nepal, Earthquake on 25 April 2015 From Ground and Spaceborne Observations

On the Co‐Seismic Ionospheric Disturbances (CIDs) in the Rapid Run Ionosonde Observations Over Allahabad Following Mw 7.8 Nepal Earthquake on April 25, 2015

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Coseismic Contortion and Coupled Nocturnal Ionospheric Perturbations During 2016 Kaikoura, M_w 7.8 New Zealand Earthquake

Coseismic Contortion and Coupled Nocturnal Ionospheric Perturbations During 2016 Kaikoura, M_w 7.8 New Zealand Earthquake

Coseismic Traveling Ionospheric Disturbances during the M_w 7.8 Gorkha, Nepal, Earthquake on 25 April 2015 From Ground and Spaceborne Observations

On the Co‐Seismic Ionospheric Disturbances (CIDs) in the Rapid Run Ionosonde Observations Over Allahabad Following M_w 7.8 Nepal Earthquake on April 25, 2015