Multi-Sensor Trajectory Reconstruction of the 24 April 2025 Alaska Fireball and Implications for Planetary Defense

TL;DR

This study demonstrates how dense ground-based seismoacoustic networks can accurately reconstruct the trajectory and characteristics of a high-altitude fireball, enhancing planetary defense capabilities especially in challenging detection environments.

Contribution

The paper introduces a multi-sensor approach combining seismoacoustic, radar, and optical data to precisely reconstruct a fireball's trajectory, energy, and composition, advancing planetary defense methods.

Findings

Trajectory reconstructed with high accuracy using seismoacoustic data

Radar and optical data confirmed the trajectory and physical parameters

Event demonstrated the importance of ground-based networks in high-latitude detection

Abstract

On 24 April 2025 at 18:30:57 UTC, a bright daytime fireball over Southcentral Alaska was detected by 37 seismic stations, 16 single infrasound sensors, and four infrasound arrays, yielding 30 ballistic and multiple fragmentation arrivals. The unprecedented density of seismoacoustic coverage enabled detailed reconstruction of the event using acoustic signals, with fragmentation source locations further guiding the identification of Doppler weather radar signatures of a meteorite fall. Incorporation of a radar-derived terminal point yielded a final trajectory solution, which agreed closely with an independent optical trajectory solution from video analysis. The reconstructed entry parameters from seismoacoustic analysis indicate a velocity of 25.3 km/s, an entry angle of 19{\deg}, and an energy release of ~38 t TNT equivalent. Assuming a chondritic composition, the pre-entry object diameter was ~0.7 m. Using orbital parameters from the optical solution, we estimate meteoroid composition as most likely a L-type ordinary chondrite. The event occurred in the sub-Arctic, where space-based optical systems face challenges in detection, demonstrating the critical role of dense ground-based seismoacoustic networks in characterizing highlatitude atmospheric entries. This uniquely well-recorded event demonstrates the capability of dense seismoacoustic networks to constrain bolide trajectories, energetics, and fragmentation, with radar and optical data providing critical confirmation and complementary perspectives. These results bridge the methodological gap between planetary-defense monitoring of natural impactors and space-traffic analyses of artificial reentries, illustrating how multi-sensor integration can deliver calibration-grade trajectories even for unpredicted events.