>But the ocean is a noisy place, and Kadri said the underwater sounds might have also been caused by underwater earthquakes...<p>Seismic is rough. Even large earthquake events are localized with large error because of constant noise - seismic event arrivals are hard to pinpoint precisely in time. On top of that, once we have arrival times from a bunch of seismometers(microphones) localization is an inversion problem, dependent on velocity models for a rather heterogeneous earth which further reduces location precision. Even worse, I doubt a crashing jet produces a large magnitude (loud) seismic event, so picking out its arrival in noisy mic data is even harder than it can be for shallow earthquakes.<p>I'd guess a radius on the order of thousands of miles at best, but it's all contingent on how loud the event was and how noisy the mics that picked it up are.