HVO: Seismic swarm at Kīlauea abated over past 24 hours

A swarm of earthquakes that began June 27 at the upper East Rift Zone of Kīlauea volcano — just southeast of the summit region — abated on Monday, according to a Hawaiian Volcano Observatory (HVO) daily status report given at 7:35 a.m. Tuesday morning.

This longer-term, gradual inflation of the summit and upper rift zones has persisted since the end of the June 3, 2024 eruption.

Any substantial increases in seismicity and/or deformation could result in a new eruptive episode, but there are no signs of an imminent eruption at this time, said HVO.

There were approximately 70 earthquakes detected beneath the upper East Rift Zone over the past 24 hours, mostly at depths of one to three kilometers (0.6–1.8 miles). This daily count is higher than background levels and similar to those recorded prior to the June 27 swarm.

Hazards remain around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes within the area closed to the public. This underscores the extremely hazardous nature of the rim surrounding Halemaʻumaʻu crater, an area that has been closed to the public since early 2008.

Near the recent Southwest Rift Zone eruption site, minor to severe ground fractures and subsidence features may continue to widen and offset, may have unstable overhanging edges, and should be avoided. Hazards associated with the recent lava flows include glassy (sharp) surfaces that can cause serious abrasions, and lacerations upon contact with unprotected or exposed skin; uneven and rough terrain that can lead to falls and other injuries; or, locally elevated levels of volcanic gases that can lead to breathing difficulty. For discussion of Kīlauea hazards, see: https://www.usgs.gov/observatories/hawaiian-volcano-observatory/hazards.

In the past day, summit tiltmeters began tracking inflationary ground deformation after a multi-day pause: the UWE instrument northwest of the summit and the SDH instrument southwest of the summit respectively recorded approximately seven and three microradians of inflationary tilt over the past 24 hours. GPS instruments around the summit region continue to show longer-term, gradual inflation since the end of the June 3, 2024 eruption. The most recent measurement of the summit’s SO₂ emission rate was approximately 75 tonnes per day on June 28, 2024.

Rates of seismicity and ground deformation beneath the middle and lower East Rift Zone and lower Southwest Rift Zone remain low. Recent eruptive activity and ongoing unrest have been restricted to the summit and upper rift zone regions. Measurements from continuous gas monitoring stations downwind of Puʻuʻōʻō in the middle East Rift Zone—the site of 1983–2018 eruptive activity—remain below detection limits for SO₂, indicating that SO₂ emissions from Puʻuʻōʻō are negligible.

Following the eruption on June 3, 2024, magma has been repressurizing the storage system beneath Halemaʻumaʻu and the south caldera region, activating earthquakes in the caldera south of Halemaʻumaʻu and in the upper East Rift Zone. At this time, it is not possible to say whether this activity will lead to an intrusion or eruption in the near future, or simply continue as seismic unrest at depth. Changes in the character and location of unrest can occur quickly, as can the potential for eruption, but there are no signs of an imminent eruption at this time.

The Hawaiian Volcano Observatory continues to closely monitor Kīlauea Volcano and will continue to provide daily Kīlauea updates. Should volcanic activity change significantly, a Volcanic Activity Notice will be issued.