The volcano known as Kilauea is located on the southeast coast of the Hawai'i (the Big Island) at about 11,000 feet above the Pacific Ocean. It has been erupting continuously since 1983 and is known as one of the most active volcanoes on earth.
The pattern of Kilauea's eruptions changed at the end of this May when measurements from the Hawaii Volcano Observatory showed that the ground around the volcano had begun to sag as the magma chamber that feeds Kilauea emptied while the land in the Lower East Rift Zone (LERZ), about 10 miles from Kilauea had begun to expand as this magma flowed into the cracks and openings in the rift zone rocks.
Because magma is a product of rocks melted under very high pressure, it contains not just minerals but also dissolved gases, therefore as the magma rises, and the pressure goes down, the magma expands, probing as it were for any weakness in the surrounding rock that might be exploited by the expanding magma.
This explains what happened on May 3 in the LERZ, which is not empty wilderness but a housing development of homes set amid a picturesque tropical paradise. On that day a 150-foot-long fissure opened spouting bright red lava and occasionally generating small explosions as the dissolved sulfur dioxide and carbon dioxide burst out of solution.
The Hawaiian Islands have long been known to have been volcanic in origin. According to the legends of the Polynesian mariners who discovered and settled the island chain some 800 years ago it was Pele the goddess of fire who had led them there and that she now resides in the Kilauea volcano.
Scientists have also long recognized the volcanic origins of the islands but had no good geological explanation for why the chain of islands lies in a nearly straight line beginning with Hawaii in the east and extending off to the northwest. Nor was there an explanation for why there is volcanic activity on the island of Hawaii while its neighboring islands are not now volcanically active.
The solution did not come until the decade 1960-70.
In face, before 1970, geology had no way to explain most geological features including mountains, oceans, earthquakes, or volcanoes. For example, the only way it could explain mountain-building was to assert that as earth cooled, its crust wrinkled, "like a drying apple."
It was the adoption of plate tectonics during the decade 1960-70 that provided geology with a fundamental theory to explain how the outer layers of the earth move and deform. It is difficult to overstate the impact of plate tectonics on geological science. "Since the development of the theory, geologists have had to reexamine almost every aspect of Geology." (Nelson, 2015)
Plate tectonics had gestated during the first half of the twentieth century, as investigations began to uncover convincing evidence that Earth's crust was in constant motion and most geological features were a consequence of that motion.
By the early 1960s much of the theory had been established.
However, the unsolved mysteries of the Hawaiian island chain seemed to be evidence against the theory because volcanic activity, such as that which would create an island chain, should occur where plates collided not in the middle of a plate as in the case of Hawaii.
It was a series of articles by a Canadian geophysicist named John Tuzo Wilson written during the years 1961-1966 that convinced even the plate tectonic skeptics. The power of Wilson's argument from evidence was described by a previously skeptical geologist as "the Tuzo hurricane," and who concluded that when the hurricane had passed "the essential notions of plate tectonics has been established." (West et al,, 2013, p. xxii)
One of the papers, published in 1963, "A Possible Origin of the Hawaiian Islands," solved the Hawaiian mysteries in terms of plate tectonics.
Wilson's proposed solution began with the hypothesis that below the oceanic crustal plate was a more or less stationary source of heat which he called a "streaming point" but which now is known as a "mantle plume" or as a "hot spot" (as, for example, in South Carolina Science Standards 8.E.5B.1). The mantle plume/hot spot is the source of the basaltic magma characteristic of the Hawaiian chain. Wilson wrote: "It is suggested that the [hot spot] gives rise to a succession of volcanoes. For example, Mauna Loa and Kilauea, which lie at the upstream end of the Hawaiian Islands...A convection current moving northwesterly over this source may have carried the succession of older volcanoes in turn away to the northwest. Each volcano, as it was carried away from its source slowly became inactive. The source soon created a new volcano in place of the old. As a result, each volcano has gone through the same life cycle...The farther a volcano is from the East Pacific Rise, the older it is. The longer a chain the older is the chain." The picture is from the original article as published in the Canadian Journal of Physics in 1963. (Wilson, 1963, p. 869)
Wilson's proposed solution is supported by subsequent research and is essentially what is presented as the story of The Formation of the Hawaiian Islands on the University of Hawaii's Hawaii Center for Volcanology website. Just as Wilson predicted, the farther from Hawaii, the older the volcano, and as illustrated in the graph, the oldest volcano is 5,000 km in distance and 70,000,000 years in time from Kilauea.
A sound theory not only explains the current state of affairs, it also has predictive power. According to Wilson's plate tectonic model, at some point in the future the island of Hawaii will move away from the hot spot and be replaced by a new island. True to the theory, there is now the beginnings of a new island called Loihi.
Note: Before 1965, what is now called "plate tectonics" was referred to as mountain building. The name "plate" for the sea floor and continental parts of the crust was coined by John Tuzo Wilson in a 1965 article, part of the Tuzo Hurricane!
The go-to source of information about the Hawaiian volcanoes is the Hawaii Volcano Observatory at https://volcanoes.usgs.gov/observatories/hvo/
Nelson, S. A. (2015). Continental Drift, Sea Floor Spreading and Plate Tectonics. Retrieved from https://www.tulane.edu/~sanelson/eens1110/pltect.htm
West, G. F., Farquhar, R. M., Garland, G. D., Walls, H. C., Morley, L. W., & Russell, R. D. (2013). John Tuzo Wilson: a man who moved mountains. Canadian Journal of Earth Sciences, 51, xv.
Wilson, J. T. (1963). A Possible Origin of the Hawaiian Islands. Canadian Journal of Physics, 41, 863-870.
page 4: graphic from Wilson, J.T. cited above.
Page 5: Graph is from The Formation of the Hawaiian Islands
Page 5: Loihi graphic is from Earth Hot Spots
Dr. John Holton
Dr. John Holton joined the S²TEM Centers SC in July of 2013, as a research associate with an emphasis on the STEM literature including state and local STEM plans from around the nation.