Megalodon or Myth? the Shocking Reality Behind the Ocean's Loudest Sound
By Maya Lin-Takahashi
The United States Navy originally deployed the Sound Surveillance System (SOSUS) during the Cold War to track Soviet submarines moving through critical oceanic choke points. In the 1990s, as military tensions eased, civilian researchers gained access to these classified underwater microphone networks. NOAA’s Pacific Marine Environmental Laboratory (PMEL) began utilizing the deep-sea sound recording infrastructure to track marine mammals, undersea volcanism, and tectonic activity along oceanic ridges.
In May 1997, NOAA hydrophones anchored thousands of meters below the surface registered an unprecedented acoustic burst. Originating in the remote South Pacific, the pulse registered around 50° S and 100° W. The sound possessed staggering power. It traveled effortlessly through the SOFAR (Sound Fixing and Ranging) channel, a horizontal layer of seawater where temperature and pressure allow low-frequency acoustic energy to propagate across thousands of miles without significant dissipation.
NOAA oceanographer Christopher Fox and his team analyzed the spectrograms with genuine perplexity. The frequency began low, curved upward, and faded out in roughly a minute. At the time, known biological sounds, including the deepest blue whale vocalization, could not match the raw decibel volume of this signal. A whale call can travel hundreds of miles under optimal ocean conditions, yet the 1997 sound traversed entire ocean basins. That sheer acoustic footprint spawned decades of wild speculation.
Maya is a hardware enthusiast who tests and reviews smart home devices, smartphones, wearables, and audio gear. She focuses on practical consumer value and build quality.
