Activity Summary:  Kīlauea volcano is not erupting. The significant increase in seismicity beneath the upper East Rift Zone and caldera south of Halemaʻumaʻu that began early yesterday is continuing with little change. Updates are being provided daily while the heightened state of unrest continues.

Summit and upper East Rift Zone Observations:  Earthquake activity increased sharply just after midnight on April 27 beneath the upper East Rift Zone (between Puhimau Crater and Hilina Pali road) and beneath Kīlauea caldera south of Halemaʻumaʻu. Earthquakes are occurring at depths of 1.5-2.5 km (1-1.5 miles) beneath the surface. Earthquakes are occurring at rates of 10-15 per hour, compared to 2-5 per hour before April 27. Over the past 24 hours there were over 250 earthquakes beneath the upper East Rift Zone and about 50 earthquakes beneath the southern end of Kīlauea caldera. The largest earthquakes were between magnitudes 2 and 3, but most earthquakes were smaller than magnitude-2. Deeper earthquakes that were occurring 5-10 km (3-6 miles) directly beneath Kīlauea caldera over the past few weeks have ceased. Kīlaueaʻs summit remains inflated. Overall ground deformation rates remain low, with ongoing inflation of the summit and uplift south of the caldera. Tiltmeters near Uēkahuna and Sand Hill showed decreased rates of inflation and uplift overnight with the onset of a deflation-inflation (DI) event. Sulfur dioxide (SO₂) gas emission rates remain low. An SO₂ emission rate of approximately 52 tonnes per day was recorded on April 23.

Rift Zone Observations:  All seismic activity on the East Rift Zone is confined to the upper East Rift Zone, with no significant earthquakes or deformation occurring past the Mauna Ulu region. Seismicity in Kīlauea's Southwest Rift Zone remains low overall. Measurements from continuous gas monitoring stations downwind of Puʻuʻōʻō in the middle East Rift Zone—the site of 1983–2018 eruptive activity—continue to be below detection limits for SO₂, indicating that SO₂ emissions Puʻuʻōʻō are negligible.

Analysis: At this time, it is not possible to say with certainty if this increase in activity will lead to an eruption in the near future – or simply remain confined below ground. However, an eruption in Kīlauea’s summit region or beneath the upper East Rift Zone, within Hawai‘i Volcanoes National Park, is one potential outcome.

UPDATES: The USGS Hawaiian Volcano Observatory (HVO) will provide daily updates while at a heightened state of unrest.

HVO continues to closely monitor Kīlauea for signs of increasing activity. Should volcanic activity change significantly, a Volcanic Activity Notice will be issued.  

Hazards are still present on Kīlauea and are described below. Residents and visitors should stay informed and follow County of Hawai‘i and Hawaiʻi Volcanoes National Park guidelines.  

Hazard Analysis:  Levels of volcanic gases (sulfur dioxide and carbon dioxide) can remain locally hazardous even when Kīlauea is not erupting. Local concentrations of sulfur dioxide (SO₂) and/or hydrogen sulfide (H₂S) may persist in downwind areas, and residents may notice odors of these gases occasionally. Significant hazards also remain around Halemaʻumaʻu from crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes within the area closed to the public. For discussion of Kīlauea hazards, please see: https://www.usgs.gov/observatories/hawaiian-volcano-observatory/hazards.