Cross-Validation of Infrasound Detections and Fireball Observations from the Global Fireball Observatory
How do infrasound signals from fireballs relate to atmospheric entry conditions and the physical properties of their parents meteoroids? In this study, we investigate the detectability of infrasound generated by local-to-regional fireballs and use the associated signals to constrain meteoroid physical properties. Across Western Australia and California, the Global Fireball Observatory (GFO) recorded nearly 300 fireball events with well-constrained trajectories within 500 km of an infrasound array over an 11-year period. Of these, 20 fireballs were confidently associated with infrasound detections. For these events, we estimate energies, constrain source altitudes using atmospheric ray-tracing simulations, and investigate source mechanisms using a multi-diagnostic approach. In particular, we examine whether the recorded infrasonic signals originated from cylindrical line sources (ballistic shocks) or discrete fragmentation episodes. Our results show that infrasound-detected fireballs span a broad range of dynamical and physical properties. This variability indicates that infrasound detectability is governed by a combination of source characteristics, atmospheric propagation conditions, and source-receiver geometry, rather than any single entry parameter. Analysis of the fireball shock source mechanisms reveals an even contribution from both ballistic and fragmentation-related sources. These results also demonstrate the value of combining infrasound and optical observations for robust constraints on meteoroid shock generation processes.