Nonlinear acoustic waves in the viscous thermosphere and ionosphere above earthquake

0468191 - ÚFA 2017 RIV US eng J - Journal Article
Chum, Jaroslav - Cabrera, M. A. - Mošna, Zbyšek - Fagre, M. - Baše, Jiří - Fišer, Jiří
Nonlinear acoustic waves in the viscous thermosphere and ionosphere above earthquake.
Journal of Geophysical Research-Space Physics. Roč. 121, č. 12 (2016), s. 12126-12137. ISSN 2169-9380. E-ISSN 2169-9402
R&D Projects: GA ČR(CZ) GC15-07281J
Institutional support: RVO:68378289
Keywords : infrasound * seismic waves * ionosphere * nonlinear wave propagation * viscosity * dissipation * remote sensing
Subject RIV: BL - Plasma and Gas Discharge Physics
Impact factor: 2.733, year: 2016
http://onlinelibrary.wiley.com/doi/10.1002/2016JA023450/full

The nonlinear behavior of acoustic waves and their dissipation in the upper atmosphere is studied on the example of infrasound waves generated by vertical motion of the ground surface during the Mw 8.3 earthquake that occurred about 46km from Illapel, Chile on 16 September 2015. To conserve energy, the amplitude of infrasound waves initially increased as the waves propagated upward to the rarefied air.When the velocities of air particles became comparable with the local sound speed, the nonlinear effects started to play an important role. Consequently, the shape of waveform changed significantly with increasing height, and the original wave packet transformed to the “N‐shaped” pulse resembling a shock wave. A unique observation by the continuous Doppler sounder at the altitude of about 195km is in good agreement with full wave numerical simulation that uses as boundary condition the measured vertical motion of the ground surface.
Permanent Link: http://hdl.handle.net/11104/0266039