Email Peter Sur at psur@hawaiitribune-herald.com.
By PETER SUR
Tribune-Herald staff writer
Before the first geologist arrived at Kilauea, the old Hawaiians had as good a guess as anybody at the time about how volcanoes worked.
During his visit to Kilauea in 1823, the missionary William Ellis was told by his Hawaiian guides about many eruptions on the flanks of the volcano, “on which occasions they supposed Pele went by a road under ground from her house in the crater to the shore.”
That’s the general idea behind rift zone eruptions on Kilauea’s flank. Ellis goes on to speculate about the source of the active lava lakes he saw in Kilauea caldera: “Perforated with innumerable apertures in the shape of craters, the island forms a hollow cone over one vast furnace.” This idea has been discredited.
Expeditions in 1840 and 1895 got closer to the source of understanding why the volcanoes erupt, but it took the arrival of Thomas A. Jaggar to begin a century of continuous scientific observations at the crater.
Jaggar stepped off the S.S. Mauna Kea on Jan. 17, 1912, and the Hawaii Herald noted his arrival with the following commentary:
“He declares Kilauea most suitable for scientific work and comes with a mighty good impression of Pele’s conduct. He says a great vertical shaft is open at Kilauea, leading down into the bowels of the Earth, and that this sort of elevator shaft contains a liquid which rises and falls and emits gases, and that there are never disastrous explosions.”
It’s fair to say that the great scientist was not so great at understanding Kilauea when he stepped off the boat. The 1912 article sheds light on the purpose of Jaggar’s observatory:
“The aim of the continued observations at Kilauea is to establish more firmly the belief that the time when volcanoes will tend to erupt may be closely foretold. The (Massachusetts) institute of technology was one of the prime movers in the study of the new science of ‘volcanic prediction,’ and it was fitting that this school should have the honor of establishing the first United States observatory for the purpose of its development.”
Jaggar would stay for only six weeks at first before leaving due to a family emergency. His early observations were based on misconceptions of the nature of volcanoes, among them the belief that volcanic gases did not contain water. But he wrote of a phenomenon that is now recognized as vog:
“The gases from the molten lava are dry,” he wrote in the Feb. 1 edition of the Herald. “When they are brownish or whitish, it is solid fume particles which show, and this matter is not evanescent, but floats away to leeward for miles. The particles are probably chlorides.”
As geologists know now, vog is comprised of a mixture of gases that mix with moisture, oxygen and sunlight to form aerosols. There is water in the fume, as Jaggar would soon learn, but no chloride elements.
The work that Jaggar contributed to the study of volcanoes in the ensuing decades would fill thousands of pages. By the time he retired from the Hawaiian Volcano Observatory, his observations had repudiated much of what he thought he knew in 1912.
As Jaggar reminisced in 1945 in a publication titled “Volcanoes Declare War”: “What have we learned there? That the lava is not liquid at all, but a hard red hot body. That the seeming liquid is a form of burning gases and glass melted by them. That this oxidation heat is mostly near the surface and perhaps the deep heat is only moderate. That the gases are terribly explosive agents, and their restraint would mean disaster. And finally, that there is periodicity to the risings and fallings, to the recurrence of flows, to eruption in short and that earth shakings and tiltings accompany these things.”
When Jaggar retired, the theory of plate tectonics had not been fully articulated, and the theory of hot spot volcanism had not emerged.
In that same 1945 publication, he concluded that volcanoes arose from intrusions in “linear fissure systems of primitive origin.”
For all his careful precision in observations, Jaggar was not sensitive to the concerns of Hawaiian cultural practitioners over their regard of the goddess Pele. He played a role in recommending the Army bomb a lava flow from Mauna Loa to save Hilo, over the objections of local residents. As he wrote in a report published in January 1936:
“Legendary lore is filled with the stories of the doings of this mythical deity (Pele) … Indubitably, very many of the older natives still cling to their belief that the fiery floods pouring down the mountain are the visible effect of some insult offered to the dangerous goddess, and many are the efforts made upon such occasions to propitiate her in order that their anger may be stayed,” Jaggar noted, dismissing predictions of “dire catastrophe if her plans should be interrupted by the unbelieving white man.”
Three-quarters of a century later, through the work of senior geologist Don Swanson, a consensus is emerging that the famous Pele-Hi’iaka saga describes a massive, long-lived Puna eruption and the formation of Kilauea’s caldera. And Pele’s climactic battle with Kamapua’a — in which the pig god is chased into the sea — is believed to describe an explosive eruption.
Swanson found evidence in the geologic record for both events in A.D. 1500 and about a century later, respectively.
Perhaps the old Hawaiians were on to something.
Email Peter Sur at psur@hawaiitribune-herald.com.