Volcano Watch: Hawaiʻi’s volcanoes are quiet and it’s a bit spooky

By the US Geological Survey Hawaiian Volcano Observatory scientists and affiliates

Here in Hawaiʻi nei, we don’t have the dramatically changing leaf colors and brisk temperatures that mark the arrival of Fall. And as October arrived this year, our night skies were dark, with no warm orange glow indicative of lava erupting on the surface.

Kīlauea’s most recent eruption stopped on Sept. 16. This was the briefest of the five eruptions that have occurred at the summit of Kīlauea since 2020.  The eruption lasted about six days and, like the four eruptions before it, filled in a portion of the summit that collapsed in 2018.

Though Kīlauea is one of Earth’s most active volcanoes, periods of time with no eruptive activity on the surface are not uncommon. Since 2020, there have been periods lasting weeks to several months between eruptions and during which there is no active lava on the surface.

Prior to the recent summit eruptions, Kīlauea didn’t erupt for over two years following the large lower East Rift Zone eruption in 2018. Looking back at Kīlauea’s eruptive history over the past couple hundred years, periods of weeks to months or even sometimes years between eruptions are relatively common. The longest period without any Kīlauea eruptions over the past 200 years was abnormally long and lasted 18 years!

For USGS Hawaiian Volcano Observatory staff, these non-eruptive periods offer a bit of respite from the flurry of activity that comes with responding to increased unrest or a new eruption. However, because our volcanoes erupt so frequently, these quiet periods also come with a bit of unease. HVO staff ask themselves questions such as how long will it be until a volcano erupts again? Where and when will the next eruption take place?

HVO’s monitoring network helps us to evaluate the answers to these questions. The monitoring network continuously tracks activity beneath the surface despite the surface itself appearing still. Right now, recent ground deformation south of Kīlauea summit is beginning to slow, but an increased number of earthquakes are being detected in this region due to a seismic swarm. The rift zones of Kīlauea along with other active volcanoes in Hawaiʻi, including Mauna Loa, remain quiet. We expect to see changes to these monitoring parameters when any of Hawaiʻi’s active volcanoes begin to show signs of unrest. 

Though Hawaiʻi’s volcanoes currently aren’t erupting, other volcanoes around the world remain active. Here in the United States, Great Sitkin and Shishaldin are erupting in Alaska, generating lava flows and ash plumes in the remote Aleutian Islands. Multiple volcanoes are active in the Democratic Republic of the Congo, Ecuador, Indonesia, Japan, The Philippines, and Russia. Individual volcanoes are also active in Chile, Ethiopia, Italy, Mexico, and Papua New Guinea.  

Elsewhere in the world, volcanoes can also cause unease even when not erupting. In Italy, there is increased earthquake activity at Campi Flegrei, a caldera that includes part of the city of Naples. The dense population of people living in the vicinity of this volcanic center has garnered much attention and the situation is complicated by evacuations during previous periods of unrest there which did not escalate to eruption.

Eruptions in Hawaiʻi over the past five years have fortunately offered safe viewing, have not required evacuations, and have only minimally impacted infrastructure. However, communities living on the flanks of Hawaiʻi’s active volcanoes should always be prepared for the range of activities that Hawaiʻi’s volcanoes can exhibit. You and your family can be better prepared for one of the many natural hazards that can impact Island of Hawaiʻi residents by taking some time now, when it is quiet, to visit the Hawaiʻi County Civil Defense website on preparedness: https://www.hawaiicounty.gov/departments/civil-defense/emergency-preparedness.  Though the skies above Hawaiʻi’s volcanoes are dark right now, they will certainly be lit up by the glow of eruptions in the future.

Volcano Activity Updates

Kīlauea is not erupting. Its USGS Volcano Alert level is ADVISORY. 

The area just south of Kīlauea’s summit is currently showing signs of elevated unrest. Rates of inflationary tilt increased two days ago in the area south of the Kīlauea summit caldera and is now leveling off. A seismic swarm in the Kīlauea summit region started Oct. 5, with over 150 earthquakes in the last 24 hours. Most of the earthquakes are occurring in a region south of the caldera at depths of around 2.5–3.5 km (1.5–2 mi) below the surface. The most recent sulfur dioxide (SO2) emission rate, of approximately 150 tonnes per day, was measured on Sept. 25.

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

Webcams show no signs of activity on Mauna Loa. Seismicity remains low. Summit ground deformation rates indicate slow inflation as magma replenishes the reservoir system following the recent eruption. SO₂ emission rates are at background levels.

One earthquake was reported felt in the Hawaiian Islands during the past week: a M3.3 earthquake 1 km (0.6 mi) SW of Pāhala at 32 km (20 mi) depth on Oct. 4 at 12:11 a.m. HST.

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