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From Atlantis to El Dorado and Avalon, legends narrate how our planet is scattered with vanished realms that suffered grand declines.
Although these are often regarded as creative legends, recent research uncovers proof of a submerged landmass under the Pacific Ocean dubbed 'a lost world.'
Researchers from ETH Zurich and the California The Institute of Technology (Caltech) has discovered massive formations deep under the Pacific Ocean that 'should not be there.'
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 supposed to be’ found there.
Referred to as a significant enigma, these discoveries challenge "our present comprehension of how the planet functions," according to the scientists involved.
"Determining Earth's structure is crucial for understanding its internal movements," says the team in their paper, which was 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' .
The issue is that nobody can observe what lies beneath the Earth’s surface, and drilling deep enough to obtain rock samples from the mantle is impossible for us.
Rather, researchers examine the velocities of seismic waves – the oscillations triggered by earthquakes and blasts – as these propagate through the Earth's internal structure.
Seismograph stations capture these waves, and based on this data, specialists can deduce information regarding the Earth's architecture and makeup.
'ETH Zurich explained that this process closely resembles how medical professionals utilize ultrasound technology to visualize internal structures such as organs, muscles, or blood vessels within the body without requiring invasive procedures.'
It is widely recognized that Earth's lithosphere—the rigid, outer layer consisting of the crust and the upper part of the mantle—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 called 'subduction'.
This refers to the geological process where one tectonic plate is thrust beneath another, and gradually, over time, an entire plate can disappear.
Previously, seismologists have identified the location of submerged tectonic plates across the Earth's mantle, though this was consistently observed beneath subduction zones only.
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 utilizing seismic wave information.
They pinpointed regions beneath the Pacific that appear to be remnants of sunken tectonic plates, located far from plate edges without any geologic signs of previous subduction activity.
The Pacific Plate is essentially a single enormous tectonic slab, which means there shouldn’t be any subducting material beneath it at all.
This implies that the anomalies are not simply submerged tectonic plates. Nonetheless, identifying the actual substance or understanding its implications for the dynamic processes within the Earth remains a mystery.
"It’s akin to a physician who has spent decades using ultrasounds to study blood circulation and discovers arteries precisely where they are expected," explained co-author Professor Andreas Fichtner, a seismologist at ETH Zurich.
'If you provide him with a more advanced examination tool, he abruptly detects an artery in the gluteal region that shouldn’t actually be present. This precisely mirrors our perspective on these recent discoveries.'
Nevertheless, the researchers offer several hypotheses regarding these anomalies, suggesting that additional data about the waves—including factors beyond their velocity—would be necessary to draw any firm conclusions.
These might consist of ancient, high-silica substances that have remained within the mantle from its inception around four billion years back.
Alternatively, these areas might be regions where iron-rich rocks gather due to mantle movements occurring over billions of years.
They state in their paper, "There are multiple possible interpretations for the observation of positive wave speed anomalies within Earth’s (lower) mantle besides the existence of subducted slabs."
'Our study highlights the essential function of full waveform inversion as a crucial method for exploring the mantle.'
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