Multi‐station infrasonic observations of two large bolides: signal interpretation and implications for monitoring of atmospheric explosions

Brown, Peter

doi:10.1029/2001gl013778

Cited by 57 publications

(34 citation statements)

References 13 publications

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“…Recently, infrasound records have been combined with satellite data to estimate bolide source energies, luminous efficiencies, and to calibrate influx rates observed by satellite systems (Brown et al 2002b), while multistation recordings have been employed for bolide geolocation (Brown et al 2002c). A recent analysis of the Morávka meteorite fall (BoroviËka et al 2003a;Brown et al 2003) has placed some limits on characteristics of the shock wave source at the fireball from both the ballistic wave and fragmentation events, suggesting that the deviation of the ray normals for the fragmentation events may be as much as 30° beyond that expected from a purely cylindrical line source blast.…”

Section: Infrasonic Recordingsmentioning

confidence: 99%

Entry dynamics and acoustics/infrasonic/seismic analysis for the Neuschwanstein meteorite fall

Revelle

Brown

Spurný

2004

Meteorit & Planetary Scien

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Abstract-We have analyzed several types of data associated with the well-documented fall of the Neuschwanstein meteorites on April 6, 2002 (a total of three meteorites have been recovered). This includes ground-based photographic and radiometer data as well as infrasound and seismic data from this very significant bolide event (Spurn˝ et al. 2002(Spurn˝ et al. , 2003. We have also used these data to model the entry of Neuschwanstein, including the expected dynamics, energetics, panchromatic luminosity, and associated fragmentation effects. In addition, we have calculated the differential efficiency of acoustical waves for Neuschwanstein and used these values to compare against the efficiency calculated using available ground-based infrasound data. This new numerical technique has allowed the source height to be determined independent of ray tracing solutions. We have also carried out theoretical ray tracing for a moving point source (not strictly a cylindrical line emission) and for an infinite speed line source. In addition, we have determined the ray turning heights as a function of the source height for both initially upward and downward propagating rays, independent of the explicit ray tracing (detailed propagation path) programs. These results all agree on the origins of the acoustic emission and explicit source heights for Neuschwanstein for the strongest infrasonic signals. Calculated source energies using more than four different independent approaches agree that Neuschwanstein was certainly <500 kg in initial mass, given the initial velocity of 20.95 km/s, resulting in an initial source energy ≤0.0157-0.0276 kt TNT equivalent (4.185 × 10 12 J). Local source energies at the calculated infrasonic/seismic source altitudes are up to two orders of magnitude smaller than this initial source energy.

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Section: Infrasonic Recordingsmentioning

confidence: 99%

Entry dynamics and acoustics/infrasonic/seismic analysis for the Neuschwanstein meteorite fall

Revelle

Brown

Spurný

2004

Meteorit & Planetary Scien

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“…These calculated and real celerity ranges strongly indicate that infrasonic signals from the blastings propagated as stratospheric phases (D. J. Brown et al, 2002) to all arrays located within regional distances.…”

Section: Discussionmentioning

confidence: 95%

“…The final location was determined with the minimum residual estimated using celerities varying from 0.23 to 0.31 km/s, a range that covers stratospheric (I s ) and thermospheric (I t ) infrasound phases (D. J. Brown et al, 2002).…”

Section: Results Of the Seismo-acoustic Location Methodsmentioning

confidence: 99%

“…Simply, intersection points from pairs of these azimuth lines could be estimated as sound source locations. To determine the most probable location, all intersections were weighted by the sine of the angle of intersection, and then a weighted average position for the most probable location for the event was determined (P. G. Brown et al, 2002) and plotted as a yellow circle. The red circle indicates a location result determined from the grid-search method.…”

Section: Results Of the Seismo-acoustic Location Methodsmentioning

confidence: 99%

“…Infrasound observation has recently been widely applied to clarify natural and anthropogenic phenomena producing low-frequency acoustics in the atmosphere, such as groundcoupled air waves from large earthquakes (Le Pichon et al, 2003;Watada et al, 2006), large bolides (P. G. Brown et al, 2002), and infrasound from accidental explosions (Evers and Haak, 2007). Infrasound technology is also important for monitoring possible nuclear explosions in the framework of the Comprehensive Nuclear-Test-Ban Treaty (Bedard and Georges, 2000).…”

Section: Introductionmentioning

confidence: 99%

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Seismo-acoustic location method for small-magnitude surface explosions

2009

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The aims of this study were to develop an improved method using infrasound observations at multiple seismoacoustic arrays for locating small-magnitude surface explosions at regional distances and to apply the method to ground-truth blasting events for validation. The location method is based on a nonlinear grid search using the travel times and back azimuths of infrasonic signals generated from the surface explosions and on seismic parameters that are independently determined by routine seismic monitoring systems. Specifically, the method utilizes wind-corrected infrasonic azimuths in grid searching to constrain the grids according to nearness to feasibly real observations. Ground-truth events were recorded by a seismo-acoustic station temporarily operated inside an open-pit mine and then used to investigate the improvement by the location method. The method improved the locating of ground-truth events by approximately 50% compared to the seismic location results. Surface explosions generating both seismic and infrasonic signals could be located independently by the seismic location, infrasonic-azimuth intersection, and seismo-acoustic location method, respectively. This method can be applied to automatic seismic/infrasonic monitoring systems as an additional location tool for explosion-induced seismic events, allowing for simultaneous monitoring for surface explosions and reduced risk of false location results.

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The 2013 Russian fireball largest ever detected by CTBTO infrasound sensors

Pichon

Ceranna

Pilger

et al. 2013

Geophysical Research Letters

115

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On 15 February 2013, a large Earth‐impacting fireball disintegrated over the Ural Mountains. This extraordinary event is, together with the 1908 Tunguska fireball, among the most energetic events ever instrumentally recorded. It generated infrasound returns, after circling the globe, at distances up to ~85,000 km, and was detected at 20 infrasonic stations of the global International Monitoring System (IMS). For the first time since the establishment of the IMS infrasound network, multiple arrivals involving waves that traveled twice round the globe have been clearly identified. A preliminary estimate of the explosive energy using empirical period‐yield scaling relations gives a value of 460 kt of TNT equivalent. In the context of the future verification of the Comprehensive Nuclear‐Test‐Ban Treaty, this event provides a prominent milestone for studying in detail infrasound propagation around the globe for almost 3 days as well as for calibrating the performance of the IMS network.

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Multi‐station infrasonic observations of two large bolides: signal interpretation and implications for monitoring of atmospheric explosions

Cited by 57 publications

References 13 publications

Entry dynamics and acoustics/infrasonic/seismic analysis for the Neuschwanstein meteorite fall

Entry dynamics and acoustics/infrasonic/seismic analysis for the Neuschwanstein meteorite fall

Seismo-acoustic location method for small-magnitude surface explosions

The 2013 Russian fireball largest ever detected by CTBTO infrasound sensors

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