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A Comprehensive Analysis on Global Bolide Infrasound

Description: 

Under certain entry velocities and initial mass conditions, the interaction of a meteoroid with dense regions of the Earth’s atmosphere can produce bolides, which refer to detonating fireballs that explode at resolvable altitudes within the atmosphere. These atmospheric phenomena can generate infrasound at rates which can be processed and subsequently leveraged towards better characterization of meteoroids when other means of observation are not available. Classification of bolide infrasound is regulated by the source geometry, which corresponds to the point along the trajectory which induced a shock wave. Shock waves resulting from a fragmentation event could have spherical or quasi-spherical geometry, whereas infrasound generated via the meteoroid’s hypersonic flight has a characteristic cylindrical line source geometry. Infrasound’s low-frequency content facilitates long-range propagation at global scales. Interpretation of processing results is oftentimes complicated due to the time-sensitive nature of the atmosphere causing irreversible effects on waveform morphology.

In this study, we utilize a data-driven approach to improve characterization of bolides documented within NASA’s Center for Near-Earth Object Studies exclusively with infrasound detected by global arrays. We implement a multi-frequency array processing software, known as Cardinal, to extract directionality estimates and phase velocities, as well as quantify waveform coherence over a broadband frequency range using narrowband spacing. When appropriate, we utilize the adaptive array algorithm to better characterize the signal over sequential frequency bands and subarray configurations. Furthermore, we measure signal delay times using known infrasound propagation velocities and a start time coinciding with bolide peak brightness, typically associated with a fragmentation episode. Our work comprehensively analyzes bolide infrasound as a function of source-receiver distance, signal arrival times, event altitude, and total impact energy.

Additional Information: SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.

Session: Advancements in Forensic Seismology and Explosion Monitoring [Poster]

Type: Poster

Date: 4/17/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Miro

Student Presenter: Yes

Invited Presentation: 

Poster Number: 93

Authors