Scientists with the Hawaiian Volcano Observatory issued an information statement on Monday saying there has been a 24 hour period of “elevated unrest” at Kīlauea.
The agency reports that tremor was observed on seismic stations nearly island-wide on Monday from approximately 2:20 to.3 p.m., with the strongest at Kīlauea summit. The unrest to to the south-southwest of Kīlauea’s summit is associated with an intrusive event that began in early October, according to the HVO.
No significant changes in ground tilt were observed during this tremor event. The agency advised that Kīlauea was not erupting but said, “Unrest may continue to wax and wane with changes to the input of magma into the area. The summit of Kīlauea remains at a high level of inflation and eruptive activity at the summit is possible with little or no warning.”
The current Volcano Alert Level remains at ADVISORY. The current Aviation Color Code remains at YELLOW.
Recent Observations
The most recent eruption at Kīlauea summit ended on Sept. 16, 2023. Following this eruption, seismicity and ground deformation remained at background levels until the first week of October, according to the HVO.
The HVO reports that rates of ground deformation then began to increase, especially in the region extending from the south caldera to the Koa‘e fault zone. A series of seismic swarms began in this region on Oct. 4, 2023, peaking at more than 250 earthquakes on Oct. 5, according to the agency. Magma did not reach the surface, and rates of seismicity and deformation diminished after Oct. 5, suggesting an intrusion. Scientists report that unrest has continued to wax and wane since then.
The HVO reports that since Oct. 5, intermittent seismic swarms have continued, varying from less than 20 events per day to more than 150 events on Oct. 22. Most of the earthquakes related to this unrest have been smaller than magnitude-2 and have occurred at depths of around 1–3 km (0.6–2 mi) below the surface.
“Seismic signals indicating magma movement, such as low-frequency tremor, have also been observed at Kīlauea summit stations, most recently on the afternoon of Oct. 23, 2023,” according to the information statement.
Interpretation and Context
Details provided by USGS/HVO:
These patterns of ground deformation and earthquakes indicate that a magmatic intrusion is occurring beneath the south-southwest region of Kīlauea’s summit. Numerous intrusions have been recorded here in the past, most recently in 2021 and 2015.
In August 2021, an intrusion here occurred over about a week and was followed by an eruption within Halema‘uma‘u about a month later (the eruption that began on Sept. 29, 2021).
In May 2015, an intrusion here lasted less than a week and occurred during ongoing eruptions within Halema‘uma‘u and at Pu‘u‘ō‘ō.
Intrusions also occurred here in the 1960s, 1970s, early 1980s, and in 2006, but only one of these events led directly to an eruption in that area.
In December 1974, an intrusion began following this path southward, but then erupted as a series of short fissure segments with a total length of 5 km (3 miles) as it turned southwest.
Of note is the fact that, before the 1974 eruption, earthquakes had migrated farther southwest than HVO has observed during recent unrest.
All Kīlauea summit webcam views are available at https://www.usgs.gov/volcanoes/kilauea/summit-webcams.
Note: All HVO webcams will be offline on Wednesday, October 25, from approximately 9:00 a.m. until 11:00 a.m. HST for system maintenance.
HVO will continue to post daily updates on our web site, along with photos, videos, and maps as they are available at: https://www.usgs.gov/volcanoes/kilauea/volcano-updates.
You can also receive daily Kīlauea updates via email by subscribing to the Volcano Notification System at: http://volcanoes.usgs.gov/vns/
HVO is in frequent communication with Hawai‘i Volcanoes National Park and Hawai‘i County Civil Defense. Hawai‘i Volcanoes National Park has closed two trails in Kīlauea’s summit region given the unrest: https://www.nps.gov/havo/learn/news/20231018-nr-unrest-trail-closures.htm.
WHAT WE CAN EXPECT
Kīlauea volcano is not erupting. Unrest to the south-southwest of Kīlauea’s summit continues. It is unclear how long unrest will continue. It is not possible to say with certainty if current unrest will lead to an eruption. Although it is not possible to forecast an exact outcome, here are three possible scenarios that could play out in the coming days to weeks:
1. Magma continues to accumulate in the region south-southwest of Kīlauea’s summit, but eventually stops with no eruption.
2. Magma continues to accumulate in the region south-southwest of Kīlauea’s summit, with an eventual eruption inside the caldera, similar to recent eruptions at Halema‘uma‘u. In this scenario, we would expect to see accelerating rates of ground deformation and earthquakes beneath the caldera 1-2 hours before lava reaches the surface.
3. Magma continues to accumulate in the region south-southwest of Kīlauea’s summit, with an eventual eruption outside of the caldera, to the south or southwest. In this scenario, we would expect to see earthquake locations migrating away from the caldera, as they did prior to the December 1974 eruption, followed by accelerating rates of ground deformation and earthquakes 1-2 hours before lava reaches the surface.
No unusual activity has been noted along Kīlauea’s East Rift Zone or Southwest Rift Zone.
Original source: https://mauinow.com/2023/10/24/scientists-report-elevated-unrest-near-kilauea-summit/