Unraveling Earth's Mysterious Core-Mantle Boundary with Seismic Waves and Ancient Oceans

Earth's core remains an elusive and fascinating realm, far too deep for direct exploration. However,  scientists utilize earthquake-generated seismic waves to investigate this enigmatic area. These waves alter in speed as they travel through diverse layers, unveiling the peculiar core-mantle boundary of our planet.

The core-mantle boundary is marked by unusual structures called ultra-low velocity zones (ULVZs), where seismic waves significantly decelerate. While these zones have been widely studied, their origin and extent are yet to be fully understood.

Recent findings suggest that the presence of ULVZs at the core-mantle boundary implies they could be remnants of ancient seafloors, which were subducted into the mantle around 200 million years ago. This theory is further supported by geodynamic models.

High-resolution investigations of the southern hemisphere have been conducted using a technique that examines sound wave echoes from the core-mantle barrier. This groundbreaking study allowed scientists to analyze thousands of seismic recordings from Antarctica Dr. Edward Garnero, co-author of the research, revealed that the material's thickness varies and could indicate mountainous structures on the core, some even five times taller than Mount Everest.

Source: Science Advances ( https://doi.org/10.1126/sciadv.add4838 )