Kilauea's Most Recent Eruption

Fiona Hamilton
Apr 7
4 min read

Kilauea is well known for being the most active volcano on the planet. Already, in my lifetime there have been several notable eruptions including the devastated Leilani estates eruption. And who could forget that time when Mauna Loa, Kilauea’s sister volcano, started erupting after almost forty years! You don’t even need to look at the news to know when Kilauea is active. From tremors in the ground to the vog in the air, each eruption has its own way of announcing itself to the whole island.

Starting on December 23rd, the newest eruption has been one to remember. There have been sixteen episodes of the eruption so far. One of the most spectacular parts of it has been the over a-hundred-foot-tall lava fountains. The most recent activity ended at 12:03 pm last Wednesday, making this episode last 37 hours, one of the longer episodes so far. The title of the longest episode does go to number three, lasting over a week.

USGS photos by D. Downs

So far, all eruptive activity is only in the national park. However various other hazards have affected nearby communities. Pele’s Hair is a volcanic glass that has been stretched up to a meter in length during an eruption. It is very thin and due to its extremely light weight, can be carried far by wind and plumes from the volcano. During this most recent eruption, it has spread over nearby communities and has even tangled into tumbleweed-like shapes in some areas. Pele’s Hair isn’t dangerous and can be treated similarly to volcanic ash, though it is harder to clean up. A good rule of thumb when it comes to volcanic ash and Pele’s Hair, is to avoid it if you can. Both can cause skin and throat irritation.

USGS photo by K. Mulliken

A better-known hazard from the most recent eruption is the vog. Volcanoes emit large quantities of carbon dioxide, sulfur dioxide, and water vapor during eruptions. Vog comes primarily from sulfur dioxide and is associated with Hawaiian volcanoes in particular. SO2 reacts with sunlight, oxygen, and other particles in the atmosphere to form small particles that create a haze in the air. Most of the island is affected by these small particles, but some of the communities closer to the volcano also experience exposure to SO2 gas, which is colorless and really stinks.

Each episode is not only characterized by the obvious fountaining of the volcano but also the inflation and deflation around the summit. By measuring the average rate of inflation of the volcano and calculating the minimum inflation needed to start another episode, those studying the eruption can predict when the next episode will be. Due to the quick rebound in inflation after the deflation of episode 16, the volcano is expected to start up again sometime after this Thursday.

History

Kilauea is estimated to have first started erupting at the ocean floor between 210,000 and 280,000 years ago. Kilauea is a shield volcano, likely shifting into its shield-building phase close to 155,000 years ago. Shield volcanoes are almost entirely made of lava flows that have created a gently sloping shield shape. Some of the biggest volcanoes are shield volcanoes –including Mauna Kea, though it’s now extinct

Photo by Hawaiian Volcano Observatory

Since 1983, Kilauea has been erupting almost continuously. Most people have a general idea of how volcanoes erupt; magma rises from the ground in vents and erupts in the form of lava, creating a volcano. However, there are different styles of eruptions that can vary even within a single volcano. Kilauea eruptions have mainly been explosive or effusive during the past 2,500 years. Whether or not the eruption is explosive or effusive depends on the magma supply. When the magma has risen high enough to fill the caldera, lava pours from the volcano or fountains like it’s doing now. If the caldera floor has sunk to be close enough to the water table, water can sneak into the vents to trigger explosions through steam. A volcano known as Hunga Tonga-Hunga Ha’apai in the Kingdom of Tonga erupted in a devastating explosive event in 2022 due to water entering its magma supply, a stunning example of how dangerous such an eruption can be.

Pavlof explosive eruption. Photo by U.S. Geological Survey, 1975

It is thought that a caldera collapse over 2,000 years ago in Kilauea triggered an explosive period of over a thousand years. The most recent explosive period of Kilauea’s lasted a mere 300 years in comparison. During this long explosive time, some of the volcano’s most explosive recorded eruptions occurred. Rocks the size of golf balls fell miles away from the volcano, and in one instance almost ten-pound volcanic rocks were shot over three miles away from the summit.

Kilauea is currently in an effusive period and has been for about 200 years. However, this will not last. It is expected that the volcano will return to a long period of explosive activity, though it is not known when. The new period will likely be initiated by a caldera collapse that leads to water entering the magma chamber. For now, though, we can enjoy the beautiful lava fountains that have dominated this most recent eruption.