The rotation of the Earth’s inner core began slowing down over a decade ago, causing the length of day to change by just a moment.
Researchers at the University of Southern California (USC) Movement of the Inner Core Using earthquake data recorded from various locations earthquake Both earthquakes and nuclear tests send vibrations throughout the Earth. By measuring the speed and interaction of seismic waves within the Earth’s layers, researchers can infer the location and movement of the inner core.
This research has been ongoing since around 2010. Inner Core It is slowing down, or receding, compared to the rate it has been moving over the past few decades, and is moving slower than the Earth’s surface. statement From USC.
“The inner core’s velocity has slowed for the first time in decades,” John Bedale, a professor of geosciences at the University of Southern California and co-author of the study, said in a statement. “Other scientists have recently argued for similar or different models, but our latest work presents the most compelling conclusion.”
Related: Layers of the Earth: Exploring the Earth’s Interior and Exterior
Of earth Inner Core Earth is a hot, dense, solid sphere of iron and nickel located 3,200 miles (5,150 kilometers) below our feet. It is surrounded by a liquid iron-nickel outer core and a solid rocky mantle. A new study finds that the slowdown of the inner core is caused by convection currents within the liquid iron outer core, which helps heat the Sun. Earth’s magnetic fieldand the gravitational force of the overlying mantle.
The researchers came to their conclusion after analysing seismic data recorded from 121 repeating earthquakes that occurred around the South Sandwich Islands in the South Atlantic between 1991 and 2023, as well as data from several nuclear tests conducted around the world.
In theory, repeated earthquakes in the same location should produce identical seismograms, since they occur in the same place. Therefore, when comparing earthquake data from different locations, time It can reveal changes beneath the Earth’s surface. Subtle changes in the time it takes for seismic waves to travel through the Earth’s surface can Earth Observations made at different times in Earth’s history have revealed a slowing down of the inner core — a change that may alter the length of a day for just a moment, but not enough to be noticeable, the researchers say.
Their findings were Released June 12th Published in Nature magazine.