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From Atlantis to El Dorado and Avalon, legends narrate how our planet is scattered with vanished realms that suffered a cataclysmic end.
Although these are often regarded as creative legends, recent research uncovers proof of a 'vanished realm' under the Pacific Ocean.
Researchers from ETH Zurich and the California Researchers at the California Institute of Technology (Caltech) have discovered enormous formations deep under the Pacific Ocean that defy expectations and 'should not exist.'
This mystery material – which is making seismic waves in the region behave strangely – could be evidence of a lost land from hundreds of millions of years ago.
Based on present scientific theories, the unusual material located in the lower mantle, approximately 600 miles (1,000 km) under the ocean surface, 'is not expected to be found' there.
Referred to as a significant enigma, these discoveries challenge "our present comprehension of how the Earth functions," according to the scientists involved.
"Determining the structure of the Earth is crucial for understanding its internal dynamics," state the researchers in their paper, published in Scientific Reports .
These results indicate a greater variety of sources for these irregularities in Earth's lower mantle.
The Earth consists of three layers: the crust, the mantle, and the core, as identified subsequently. divided into 'internal' and 'external' parts .
The issue is that nobody can observe what lies within the Earth, and drilling deep enough to collect rock samples from the mantle is beyond our capabilities.
Rather, researchers examine the velocities of seismic waves – the oscillations triggered by quakes and blasts – as these propagate through the Earth's internal structure.
Seismograph stations capture these waves, and based on this data, experts can infer details about the Earth's structure and makeup.
'ETH Zurich explained that this process closely mirrors how physicians utilize ultrasound technology to visualize internal structures such as organs, muscles, or veins within the body without requiring surgical incisions.'
It is widely recognized that Earth's lithosphere—the rocky outer layer consisting of the upper part of the mantle and the crust—is made up of approximately 15 tectonic plates.
Earthquakes can be identified around the edges of tectonic plates, where these massive sections grind against one another.
However, long ago, substantial tectonic plates vanished beneath Earth's surface through a process known as 'subduction.'
This refers to the geological process where one tectonic plate is thrust beneath another, leading to the gradual subduction of an entire plate over time.
Previously, seismologists have mapped the location of submerged tectonic plates across the Earth's mantle; however, these were consistently found beneath subduction zones.
In their latest research, scientists from ETH Zurich and Caltech employed a computational method known as 'full-waveform inversion.' This approach generates a three-dimensional representation of the Earth’s structure through analysis of seismic waves.
They pinpointed regions beneath the Pacific that appear to be remnants of submerged tectonic plates, located distant from plate margins without any geologic proof of previous subduction activity.
The Pacific Plate is essentially one single tectonic plate, which means there shouldn’t be any subducting material beneath it at all.
This implies that the anomalies are not simply submerged tectonic plates. Nevertheless, identifying the actual nature of this material—or understanding its implications for the dynamic processes within the Earth—remains a mystery.
"It’s akin to a physician who has spent years using ultrasounds to study blood flow and consistently discovers arteries precisely where they should be," explained co-author Professor Andreas Fichtner, a seismologist from ETH Zurich.
'If you provide him with a more advanced examination tool, he abruptly detects an artery in the buttocks that shouldn’t actually be present. This precisely mirrors our reaction to these new discoveries.'
Nevertheless, the researchers offer several hypotheses regarding the anomalies, suggesting that these would require additional data from wave characteristics beyond mere velocity to draw any solid conclusions.
These might consist of ancient, high-silica substances that have remained within the mantle from its inception around four billion years ago.
They might also be areas where iron-rich rocks gather due to mantle activity over millions of years.
They state in their paper, "There are various possible interpretations for the observation of positive velocity anomalies within Earth’s (lower) mantle besides the existence of subducted slabs."
'Ours is the finding that highlights the essential function of full waveform inversion as a vital instrument for investigating the mantle.'
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