Scientists have found unusual areas between the Earth’s liquid core and the solid mantle layer that consists of heterogeneous structures made of hot and dense rocks.
In a new study, scientists have focused on the core-mantle boundary below the Pacific Ocean basin and found something previously unknown. They found that structures beneath the Hawaiian Islands are much larger and found new structures beneath the volcanic Marquesas Islands in the South Pacific.
Geologists use earthquakes to study the Earth’s interior in seismology. This field of study uses seismic wave generated by earthquakes just like sound waves are used in echolocation. Seismic waves can traverse thousands of miles and along the way changes in rock density, temperature or composition causes them to change speed, bend or scatter which produces echoes that are then detected using instruments called seismometers.
Based on this data, scientists are able to develop models that can describe the physical properties of these inaccessible sub-surface regions.
In their study, researchers from the University of Maryland analyzed 7,000 seismograms from hundreds of earthquakes of 6.5 magnitudes and greater occurring around the Pacific Ocean basin from 1990 to 2018 using a machine learning algorithm. The study published in the journal Science gives a comprehensive view of the core-mantle boundary below the Pacific Ocean, making it the first to cover such a wide area in detailed resolution.
Researchers were able to observe thousands of core-mantle boundary echoes at once using the machine learning-based Sequencer algorithm. Lead author of the paper, Doyeon Kim from the University of Maryland’s Department of Geology says, “This is showing us that the core-mantle boundary region has lots of structures that can produce these echoes, and that was something we didn’t realize before because we only had a narrow view.”
Researchers found echoes along about 40% of all seismic wave paths which was surprising as Co-author of the study, Vedran Lekić explains, “We were expecting them to be more rare, and what that means is the anomalous structures at the core-mantle boundary are much more widespread than previously thought.”
This news was originally published at in.mashable.com