91Ö±²¥

A series of lava fountains building -a cone perched on the crater rim … sounds like the ongoing eruption in Halema‘uma‘u at the summit of Kilauea, but this description could also fit the Kilauea Iki eruption in 1959. Let’s compare these two episodic lava fountaining eruptions.

An earthquake swarm 35 miles (55 kilometers) beneath Kilauea in August 1959 was followed in October by ground swelling indicating that magma was accumulating within the volcano.

On Nov. 14, Kilauea summit region shook for 5 hours as magma made a path to the surface. The eruption began at 8:08 p.m. as a series of small lava fountains on the south wall of Kilauea Iki Crater, east of Kaluapele (Kilauea summit caldera). Gradually over the next day, eruptive activity became focused at one vent.

For the next week, this vent continued to erupt with lava fountains reaching up to 1,200 feet (380 meters) high. Fallout from the lava fountain — tephra, fragments from volcanic eruptions that are ejected through the air — landed on the crater rim to the southwest, while lava also accumulated within the crater, forming a lava lake.

On Nov. 21, the lake of lava within the crater rose above the level of the vent. That evening, the vent abruptly stopped erupting and lava from the lake began to drain back. Over the next 5 days, pahoehoe ooze outs and crustal overturns continued on the lava lake surface within the crater. The vent crusted over, but the eruption was not over.

Just after midnight on November 26, the eruption resumed. Similar to how some episodes in the ongoing Halema‘uma‘u eruption have been slow to start, episode 2 in 1959 started with low fountains as degassed lava that had drained into the vent was erupted out. Eventually, eruption of fresher and gassier lava was accompanied by higher lava fountains reaching 1,000 feet (305 meters). The second episode lasted less than 24 hours.

In total, 17 episodes of lava fountaining occurred at Kilauea Iki over about a month in 1959. Episode 15 even saw the highest lava fountains ever recorded at Kilauea: 1,900 feet (580 meters). Tephra fell up to 10 miles (16 kilometers) downwind. Pu‘upua‘i was built as 230 feet (70 meters) of tephra piled on the crater rim, while the crater was filled with 413 feet (126 meters) of lava. During the ongoing Halema‘uma‘u eruption, 140 feet (43 meters) of tephra has accumulated on the crater rim and an average of 223 feet (68 m) of lava has been added to the crater floor.

When lava would drain back after an episode in 1959, it left a “black ledge” — like a bathtub ring — around the crater. During early episodes of the ongoing eruption in Halema‘uma‘u drainback similarly occurred, but this no longer occurs because the vent topography is now much higher than the surroundings.

Following recent episodes in Halema‘uma‘u, the cone on the crater floor and rim has developed large cracks as portions of the steep and unconsolidated slopes slump downward. This also occurred in 1959, with collapsed parts of the cone being rafted on the lava lake surface during subsequent episodes.

During the month-long Kilauea Iki eruption 1959, 13.2 billion gallons (50 million cubic meters) of lava erupted over 17 episodes. During the ongoing eruption in Halema‘uma‘u, about four times that volume has been erupted — 52.7 billion gallons (200 million cubic meters) — during a little more than twice the number of episodes, but over an entire year.

The ongoing Halema‘uma‘u eruption has surpassed Kilauea Iki in terms of longevity and erupted volume, but its lava fountains (at a maximum of 1,575 feet, or 480 meters) have not yet approached the highest observed during the Kilauea Iki eruption.

The last two episodes of the Kilauea Iki eruption occurred on the morning and evening of the same day. Episode 16 produced fountains up to 800 feet, while episode 17 only produced spatter reaching about 100 feet (30 meters). This quick drop off in activity is one scenario for how the current Halema‘uma‘u eruption could end.

After the Kilauea Iki eruption, the summit region was at a higher level of inflation than before the eruption started, leading to magma migration and an eruption on the East Rift Zone in early 1960.

Currently, the USGS 91Ö±²¥an Volcano Observatory does not see any signs of change to the current eruption and we continue to closely monitor Kilauea.

Volcano activity updates

Kilauea has been erupting episodically within the summit caldera since December 23, 2024. Its USGS Volcano Alert level is WATCH.

Episode 39 lava fountaining happened for 6 hours on Dec. 23-24. Lava fountains erupted from both the north and south vents, with maximum heights of approximately 1400 feet (425 m). The summit is reinflating and another fountaining episode is likely between Jan. 10 and 14. No unusual activity has been noted along Kilauea’s East Rift Zone or Southwest Rift Zone.

Mauna Loa is not erupting. Its USGS Volcano Alert Level is at NORMAL.

One earthquake was reported felt in the 91Ö±²¥an Islands during the past week: a M3.4 earthquake 11 km (6 mi) E of Pahala at 30 km (19 mi) depth on Jan. 1 at 10:00 p.m.

Please visit HVO’s website for past Volcano Watch articles, Kilauea and Mauna Loa updates, volcano photos, maps, recent earthquake information, and more. Email questions to askHVO@usgs.gov.