Research, led by The University of Alabama, has revealed a dense layer of ancient ocean floor, or an ultra-low velocity zone (ULVZ), near Earth’s core, according to a new study.
While Earth’s core is too deep to be directly explored, Samantha Hansen, a geophysicist and lead researcher on the project, said the team was able to use instruments to record seismic waves and signals from earthquakes.
“Some of the energy from those earthquakes traveled deep into our planet and reflected (bounced) off the core-mantle boundary (CMB), ultimately getting recorded by our Antarctic stations”.
The data suggests this layer of ocean floor may cover the core-mantle boundary. This layer is similar to “mountains” – a reasonable analogy according to Hansen – due to its variable structure along Earth’s core that is thinner in some places and thicker in others.
“This is similar to a mountain range, where the peaks can have different elevations. And, just like mountains at the surface of the Earth, this structure changes with time”.
While the presence of these structures along the core is something that has been recognized in previous studies, Hansen said the team was surprised by how “abundant” the structures were, finding evidence all over the southern hemisphere.
“Combining the seismic results with the geodynamic modeling took this a step further. The consistency between them makes for a very compelling interpretation”.
The team is currently working on expanding the Antarctic-based study by examining data from all available seismic networks across the continent. Hansen said they would like to apply other analyses and modeling approaches to further analyze the characteristics of ULVZs.
“I hope that readers take away an appreciation for how complex and fascinating our planet is,”.
“There are still many unknowns about the world beneath our feet and even small-scale structures like the ULVZs we’ve imaged can play major roles in how our planet functions.”
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