Activity Summary:  Kīlauea volcano is not erupting. Elevated seismicity beneath the upper East Rift Zone and caldera south of Halemaʻumaʻu that began on April 27 continues. 

Summit and upper East Rift Zone Observations:  An increase in earthquake activity began just after midnight on April 27 beneath the upper East Rift Zone and beneath Kīlauea caldera south of Halemaʻumaʻu. Over the past few days, earthquake locations have been focused primarily between the southeast side of Kīlauea caldera beneath Keanakākoʻi crater and the intersection with Hilina Pali Road. The number of earthquakes is similar to yesterday with approximately 270 earthquakes in this area over the past 24 hours. However, since midnight hourly earthquake activity has increased from 10-12 earthquakes per hour to 12-15 earthquakes per hour with most of the activity southeast of Puhimau crater. Depths remain concentrated between 2-3 km (1.2-1.9 miles) beneath the surface with scattered shallower earthquakes. There have been few earthquakes in the caldera south of Halemaʻumaʻu over this same period. Earthquake magnitudes in both areas have not exceeded M3.0 in the past 24 hours, with the vast majority below M2.0. Since the start of the unrest, there have been over 1500 earthquakes beneath the upper East Rift Zone and approximately 225 earthquakes beneath the southern end of Kīlauea caldera.

Ground deformation continues with ongoing uplift at the summit and south of the caldera into the Southwest Rift Zone. Around 1:00 PM yesterday, the tilt signal at Uēkahuna turned over to inflation as part of a deflation-inflation (DI) event that began on 29 April at 6:00 PM.  Inflation slowed at around 9 PM and continues at this rate this morning. The Sand Hill tiltmeter continues to record steady inflation of the south end of the caldera and increased slightly around 9 PM to rates observed this morning.

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 occurring past the Mauna Ulu region. At this time, there are still no signs of deformation beneath the upper East Rift Zone beyond Keanakākoʻi crater. 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 intrusion or eruption in the near future – or simply continue as seismic unrest at depth. The upper East Rift Zone is currently being pressurized by inflation of the main magma reservoir beneath the southern end of Kīlauea caldera and south of Keanakākoʻi crater within Hawai‘i Volcanoes National Park. The upper East Rift Zone is reacting to this pressurization.  While both inflation and earthquake counts increased overnight, they remain below the peak values recorded several days ago. The current intensity of seismic swarms suggests that formation of a dike beneath the upper East Rift Zone or Kīlauea caldera is a potential outcome. However, if a dike is emplaced beneath the upper East Rift Zone, there is a much higher historical probability of it resulting in an intrusion (where magma remains below the surface) than as an eruption (where the dike breaks the surface). In either case, dike emplacement from these shallow depths can take place with very little warning. Both intrusions and eruptions can cause significant surface cracking that can render roadways in the area impassable.

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.