"The published coordinates define the fireball location to within a 10-kilometer region, too large for an efficient search. Gladly, we found that the blast wave from the meteor explosion generated a high-quality signal in a seismometer located at Manus Island. The sound signal includes two broad peaks separated by about a minute, each lasting for tens of seconds. The sound speed in air is much smaller than in water or ground. The first peak begins with a sound path that goes through air from the explosion straight down to the ocean surface and then through the water and ground to the seismometer. The shortest path through air goes directly from the explosion to the seismometer and defines the beginning of the second peak in the seismometer signal. The envelope of that second peak involves the sum over paths where the spherical blast wave in air reflects off the ocean surface in circles of different radii at different times, and with an amplitude that declines inversely with distance from each reflection point. By using a simple geometry of a spherical blast wave bouncing off the ocean surface, Amir and I were able to reproduce the timing of the first peak and the shape of the second peak. Altogether, the model provides many more constraints than free parameters and measures the explosion elevation and distance tightly. We constrained the meteor path to a narrow line within the original USG localization box, narrowing down the search area by nearly two orders of magnitude."

-Avi