Hawaii Volcanoes National Park. Lava tree mold with pieces of partly charred wood, which are remnants of the top of tree, on the 1823 lava flow of Kilauea Volcano. Photo by H.T. Stearns, July 11, 1924.

(Volcano Watch is a weekly article written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.)

William Ellis

William Ellis led a team of missionaries on a tour of the Island of Hawaiʻi starting on July 18, 1823, from the village of Kailua. Their trip took them around the southern coast of the island and inland through the east Kaʻū District. When they were in the vicinity of Kapāpala, a short distance northeast of Pāhala, their attention was drawn to some rising columns of “smoke” a few miles away.

The next morning, they decided to investigate and discovered a very recent fissure eruption along the southwest rift zone of Kīlauea Volcano. Later geological studies revealed that the source of this eruption was a 9.2 km-long (5.7 mi-long) fissure that fed lava to the south into the sea. There were no spatter cones built by the eruption, and the lava seemed to have moved quickly. “The inundation was sudden and violent, burnt one canoe, and carried off four more into the ocean” according to William Ellis, chronicler of this island tour.

A nearby farmer informed them that the fissures opened about “11 moons” earlier, followed by a slight earthquake “2 moons” before their visit. The eruption probably occurred sometime after the earthquake. The area was still too hot for the missionaries to stand for long, so they moved on toward the volcano, Kīlauea.

Ancient Hawaiian trail of smooth stone across the 1823 Keaiwa (seaward) flow of Kilauea Volcano. Photo taken July 10, 1924.

The next day, August 1, 1823, the group arrived at Kīlauea Crater. “After walking some distance … we … came to the edge of the great crater, where a spectacle, sublime and even appalling, presented itself before us.… Astonishment and awe for some moments rendered us mute, and, like statues, we stood fixed to the spot, with our eyes riveted on the abyss below.”

They were the first to publish a description of Kīlauea Crater. About 150 m (500 ft) below the crater’s rim, there was a “black ledge” of hardened crust extending all the way around the inside of the crater, with the floor a few hundred meters below. At the time of their visit, the floor of the crater “was covered with lava,” probably an active lava lake.

“It was evident that the large crater had been recently filled with liquid lava up to this black ledge, and had … emptied itself into the sea … in all probability this evacuation had caused the inundation of the Kapapala coast … about three weeks prior to our visit,” Ellis wrote. This deduction was very astute.

During repeat visits to the crater over the next two years, the missionaries observed that the level of activity decreased with each visit and that the crater was filling up.

Hawaii Volcanoes National Park. Lava ball from the 1823 lava flow of Kilauea Volcano on the wall of the Great Crack near Puna trail crossing. Photo taken in 1924.

The missionaries had stumbled on a fundamental behavior of KÄ«lauea volcano: the crater floor subsides and lava drains away, often fueling an eruption along one of its two rift zones, only to slowly refill before the process starts again.

The next of these subsidences occurred early in 1832. Missionary Sheldon Dibble, who resided in Hilo, experienced earthquakes and saw an increase in the glow visible from the volcano. Almost two weeks later, Dibble traveled to the crater and saw what had happened. The bit of crater rim between Kīlauea and Kīlauea Iki Crater (now called Byron’s Ledge) had been “rent by the convulsive throes which shook the whole island.” Lava poured into Kīlauea Iki Crater, and the floor of Kīlauea Crater subsided, just as it did in 1823.

The sequence replayed in the spring of 1840 when a voluminous eruption of lava, which started high on the volcano’s East Rift Zone, kept erupting from fresh fissures lower on the rift zone and ultimately entered the ocean north of Kapoho. Again, Kīlauea Crater had filled between 1832 and 1840, and the floor had subsided, coincident with the East Rift Zone eruption. The 1840 eruption was missionary Titus Coan’s introduction to Kīlauea’s sequence.

Hawaii Volcanoes National Park. Lava tree mold on the 1823 flow of Kilauea Volcano near upper Puna trail. 1924. Photo by W.O. Clark.

The same sequence, but on a smaller scale, occurs at the Pu‘u ‘Ō‘ō vent. Over the past several years, the crater floor subsided and refilled, only to subside again, coincident with an outpouring of lava from somewhere nearby. The sequence occurred three times in 2011 and, most recently, on June 27, 2014.

Recognizing this sequential behavior allows us some ability to forecast what volcanic activity might come next, but not when. To improve our forecasts, we continue to look for the clues to help us understand the timing of the sequence.