For the first time, an international team of geophysicists has succeeded in monitoring the formation of a new oceanic crust in real time.
Royer from the French National Centre for Scientific Research (CNRS) deployed five hydrophones (water microphones) near Amsterdam Island in the Indian Ocean to record underwater seismic waves. The scientists expected to detect limited movements on the ocean floor, but were surprised by a completely different phenomenon.
This phenomenon occurred in the southeastern Indian Ocean Ridge, located between Australia and Antarctica, where tectonic plates diverge and magma rises from deep within the Earth, then cools to form new oceanic crust. Although this process has been ongoing for billions of years, no one has been able to observe it directly before.
Over a period of 16 days, approximately 150 million cubic meters of magma surged into the Earth's crust, causing the seabed to subside by 4.2 meters. The mountain range also shifted by between two and four meters, equivalent to the movement that typically occurs over a 30- to 60-year period of natural plate divergence. At its peak, the divergence rate reached 5 centimeters per minute, compared to the usual rate of 6 centimeters per year.
Roy said: "We never dreamed of recording an event of this magnitude."
The study also revealed why seismic data does not match the actual speed of plate drift, as most of these movements occur quietly, without causing noticeable earthquakes.
