Modeling propagation of infrasound signals observed by a dense seismic network.
The long-range propagation of infrasound from a surface explosion with an explosive yield of about 17.6 t TNT that occurred on June 16, 2008 at the Utah Test and Training Range (UTTR) in the western United States is simulated using an atmospheric model that includes fine-scale layered structure of the wind velocity and temperature fields. Synthetic signal parameters (waveforms, amplitudes, and travel times) are calculated using parabolic equation and ray-tracing methods for a number of ranges between 100 and 800 km from the source. The simulation shows the evolution of several branches of stratospheric and thermospheric signals with increasing range from the source. Infrasound signals calculated using a G2S (ground-to-space) atmospheric model perturbed by small-scale layered wind velocity and temperature fluctuations are shown to agree well with recordings made by the dense High Lava Plains seismic network located at an azimuth of 300° from UTTR. The waveforms of calculated infrasound arrivals are compared with those of seismic recordings. This study illustrates the utility of dense seismic networks for mapping an infrasound field with high spatial resolution. The parabolic equation calculations capture both the effect of scattering of infrasound into geometric acoustic shadow zones and significant temporal broadening of the arrivals.
Obukhov Institute of Atmospheric Physics, Moscow 119017, Russia.
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I
Chunchuzov
Obukhov Institute of Atmospheric Physics, Moscow 119017, Russia.
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S
Kulichkov
Obukhov Institute of Atmospheric Physics, Moscow 119017, Russia.
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O
Popov
Laboratory for Atmospheric Acoustics, Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, California 92093-0225.
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M
Hedlin