ANALYSIS | Hawaiian volcano eruption is explosive evidence of plate tectonic theory | 24CA News

The present eruption of Mauna Loa on the Big Island of Hawaii is a part of an extended historical past of volcanic exercise that fashioned the Hawaiian chain and is a vivid demonstration that the enormous plates of the Earth’s crust transfer over time.

If you take a look at a map of the Hawaiian islands, you will note they type a sequence that runs in a northwesterly route, with Big Island on the southern finish of the chain. It can be the one island within the group that’s volcanically lively. 

This chain of islands in the midst of the Pacific Ocean got here to the eye of Canadian geologist John Tuzo Wilson who, in 1963, proposed the concept that the islands have been created by a really lengthy lasting and very scorching spot within the Earth’s mantle. His concept was {that a} plume of molten magma that rises up from deep inside the Earth and had punched a gap by the overlying crust. 

As the recent lava flows upwards over 1000’s of years, it builds up right into a volcanic mountain that finally pokes by the ocean floor, forming an island.

This course of continues at the moment with the latest eruptions on the summit of Mauna Loa, and with ongoing eruptions on Kilauea, situated on the opposite aspect of Big Island. In different phrases, Big Island is getting greater.

But Wilson noticed one thing extra than simply the recent spot punching holes within the crust. He noticed the Hawaiian island chain as the results of a sequence of holes based mostly on the truth that rocks on the opposite islands change into progressively older as you go north. Those on Kauai, the northernmost inhabited island, are about five-and-a-half million years outdated, whereas these on Big Island are lower than a million years outdated.

He argued that the ground of the Pacific Ocean has been slowly transferring northwest, so after one volcano is constructed, the ocean flooring strikes over the stationary hotspot and one other volcanic island types. Over hundreds of thousands of years, a sequence of islands fashioned throughout the ocean. Think of transferring a sheet of paper over a candle, the place the flame can burn a sequence of holes by the paper because it strikes. 

Another scorching spot is believed to put underneath Yellowstone National Park and is liable for the quite a few scorching springs and geysers within the space. 

The idea that the ground of the Pacific Ocean is transferring offered help to the idea of continental drift, which was hotly debated amongst geologists proper into the Sixties. Wilson was instrumental in creating it additional into the present concept of plate tectonics, wherein the crust of the Earth is damaged into continent-sized items that transfer round, slowly altering the face of the planet. 

The present eruption on Mauna Loa is, in geologic phrases, kind of a final gasp as a result of a brand new volcano, Kama’ehuakanaloa — previously generally known as Loihi — is forming to the south of Big Island.

It rises greater than 3,000 metres above the ocean flooring, however its summit remains to be a couple of kilometre beneath the floor of the ocean. It is fed by the identical hotspot, in order the Pacific plate continues its gradual motion north, Kama’ehuakanaloa may burst above the waves someday sooner or later. 

The Big Island of Hawaii is an efficient place to go if you wish to see eruptions in motion, however finally, these volcanoes will go quiet. However, should you stick round for an additional 10,000 years or so, Kama’ehuakanaloa may change into the island the place folks go to see the spectacular sight of the Earth constructing new land.