The Mariana Trench Sounds - Echoes from the Deep
Challenger Deep trough in the Mariana Trench near Micronesia. Image courtesy of NOAA.

The Mariana Trench Sounds. In the deepest recesses of the ocean, where sunlight dares not venture, lies a world shrouded in mystery and darkness. Here, in the Mariana Trench, the deepest point on Earth, a series of unexplained sounds have been captured, stirring curiosity and wonder among scientists and the public alike. These enigmatic noises from the abyss have come to be known as the Mariana Trench Sounds.

The Mariana Trench, located in the western Pacific Ocean, reaches depths of nearly 11 kilometers (about 7 miles). It’s a place of extreme pressure, pitch darkness, and a seemingly alien landscape. In this otherworldly setting, hydrophones — special underwater microphones designed to operate in deep-sea environments — have picked up several unusual and mysterious sounds.

Among these enigmatic noises are the “Bloop,” “Julia,” and “Train.” These sounds, characterized by their low frequency and unique acoustic signatures, have captivated the imagination of many. The Bloop, perhaps the most famous of these sounds, was first recorded in 1997 by the U.S. National Oceanic and Atmospheric Administration (NOAA). It was a loud, ultra-low frequency sound that could be heard over 5,000 kilometers (3,000 miles) away and lasted for about one minute. Initially, its source was a complete mystery, leading to wild speculations including giant sea monsters or unknown submarine phenomena.

“Julia” is another mysterious sound, recorded in 1999, resembling a muffled moaning noise. It was loud enough to be picked up by multiple sensors across a vast area of the Pacific. “Train,” as the name suggests, sounds like a train rumbling through the deep, a slow, chugging sound that has intrigued those who have heard it.

Over time, scientists have been able to offer plausible explanations for these sounds. The Bloop, for example, is now thought to have been the noise of an icequake — the cracking and fracturing of sea ice or an iceberg scraping the ocean floor. This explanation is supported by the fact that the sound’s characteristics are consistent with those of ice-related noises commonly heard in the polar regions.

“Julia” and “Train” have similar natural explanations. “Julia” may have been the sound of a large iceberg running into the seafloor, while “Train” could be the sound of an underwater volcanic tremor. These explanations, while less sensational than the idea of unknown sea monsters, underscore the dynamic and often surprising nature of the ocean’s acoustic environment.

The deep sea, especially places as remote and inaccessible as the Mariana Trench, is a frontier for discovery on Earth. Sounds like the Bloop and Julia remind us of how much remains unknown and unexplored in the ocean depths. The mystery of these sounds has also highlighted the importance of oceanographic research and the need to better understand our planet’s underwater worlds.

The Mariana Trench sounds, though largely explained, continue to be a source of fascination. They represent the vast and mysterious nature of the ocean, a place that holds secrets yet to be unraveled. As technology advances and our ability to explore these extreme depths improves, we may soon uncover more of the ocean’s hidden symphonies, deepening our understanding of this complex and mysterious underwater world.



Don Leith

By Don Leith

Retired from the real world. A love of research left over from my days on the debate team in college long ago led me to work on this website. Granted, not all these stories are "fun" or even "trivial" But they all are either weird, unusual or even extraordinary. Working on this website is "fun" in any case. Hope you enjoy it!