Pictured: Mauna Loa’s eruption offers a rare glimpse of Earth

In 1963, a geophysicist by the name of John Tuzo Wilson proposed that the islands are covered by layers of volcanic rock, resting on a plume of magma, which forms when rock from the deep mantle rises and settles inside. under the shell. This “hot spot” continuously pushes towards the surface, sometimes through the tectonic plate, melting and deforming the surrounding rock as it moves. The plate shifts over millions of years while the magma plume is relatively stationary, creating new volcanoes atop the plate and leaving dormant volcanoes behind as they rise. The result is archipelagos such as the Hawaii-Emperor subterranean mountain chain and parts of the Icelandic plateau.

The hotspot theory gained wide consensus over the ensuing decades. “No other theory can reconcile so many observations,” said Helge Gonnermann, a volcanologist at Rice University.

Some confirmatory observations have emerged relatively recently, in the 2000s, after scientists began placing seismometers, which measure terrestrial energy waves, on the ocean floor. John Orcutt, a geophysicist at the University of California, San Diego who helped lead that study, said that seismometers provided X-rays of the magma that was forming beneath Hawaii. The devices can accurately read the direction and speed of the magma flow; The results are only clear about the presence of a hotspot.

This hotspot has probably fueled volcanic activity for tens of millions of years, although it reached its present location under Mauna Loa only about 600,000 years ago. And as long as it’s there, Dr Orcutt said, it will reliably generate volcanic activity. He added: “Few things on Earth are predictable.

Closer to the surface, it becomes more difficult to predict the time, location, and intensity of these eruptions, despite the abundance of seismometers and satellite sensors. “The deeper you go, the smoother the behavior goes,” says Dr. Orcutt. “By the time you get this interface between rock and molten rock and the ocean, magma tends to come out sporadically.”


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