For the first time, scientists have taken a proactive look at an ultra-low velocity zone. These enigmatic pockets of rock are just 3,000 kilometers below the surface.
They''re quite broad to investigate, but we know that they''re there because of the way seismic waves flow through Earth. These zones are akin to the way seismic waves slow right down as they pass through them.
Photos of these zones have been bleak and difficult to understand up until this point, but the one now published in a new study reveals a zone beneath Hawaii in much more detail, revealing new insights into our planet''s inner workings.
Nature Communications, 2022, Conceptual Drawing of the ultra-low velocity zone.
"These are the most beautiful and complex characteristics of all Earth," says geophysicist Zhi Li of the University of Cambridge in the United Kingdom.
"We''ve got the first solid evidence to show their internal structure it''s a real breakthrough in deep Earth seismology."
The most recent in computational modeling techniques were used to generate the image, and techniques applied to a high-frequency signal that was recorded as seismic waves swam through the ultra-low velocity zone.
When it comes to studying the relationship between Earth''s iron-nickel core and the mantle wrapped around it, it gives experts a kilometer-scale view of the rock pocket.
The flow of the hot mantle rock is caused by earthquakes, volcanic eruptions, and other related activities, and scientists are interested in learning more about how ultra-low velocity zones might be triggering or influencing that activity.
It''s thought that adding iron in these unusual zones might help to increase the density that shows up on seismic wave patterns, and discovering one way or another might reveal us more about how Earth formed and how it operates today.
"It''s possible that this iron-rich material is a remnant of Earth''s ancient history," says the seismologist. Sanne Cottaar, a Cambridge University professor, claims.
Scientists have discovered a link between ultra-low velocity zones and volcanic hotspots, such as those in Hawaii and Iceland. One assumption is that these hotspots may be caused by material being up from the core to the surface.
Better imagery of these deep and mysterious zones should be helpful in this field of study, and scientists are also studying basalt rock on the surface in Hawaii to uncover core leaks.
In certain cases, the study of ultra-low velocity zones is limited by where earthquakes occur and where seismographs are installed, but the research team is attempting to expand their high resolution imagery capabilities to other large areas of Earth.
"We are really pushing the limits of advanced high-performance computing for elastodynamic simulations, allowing us to take advantage of wave symmetries unnoticed or unused before," says data scientist Kuangdai Leng of the University of Oxford in the United Kingdom.
Nature Communications has published this paper.