USGS Volcano Notice - DOI-USGS-HVO-2024-01-31T10:20:40-08:00

Activity Summary:  Kīlauea volcano is not erupting.  An increase in seismicity in the south caldera region started this morning and has remained at high levels since 3 a.m. HST. Kīlauea’s summit remains pressurized; in recent months unrest has escalated quickly, and an eruption could occur in the future with little warning.  

Summit Observations:  Seismicity began to increase just before midnight. Since 3 a.m. HST, 25-30 locatable earthquakes have occurred per hour at depths of 1.5–3 km (1–2 mi) below the surface. Earthquake clusters have migrated between the area just south of Halema’uma’u and the region southwest of the outer caldera boundary. The most intense activity occurred between 6 and 8 a.m., when earthquakes were clustering just south of Halemaʻumaʻu. There have been over 180 locatable earthquakes in this region in the past 6 hours, with magnitudes ranging from a maximum of 3.4 to less than 1. Several of these earthquakes were large enough to be felt by HVO staff in the field, who also reported rockfalls on the south side of Halemaʻumaʻu.   

At the time of this report, earthquake activity remains elevated, and the overall number and intensity of earthquakes is fluctuating with time. Periods of increased seismicity can be expected to continue during repressurization of the summit magma reservoir, which has been ongoing since the end of the September 2023 eruption.  

Kīlauea's summit region remains at a high level of inflation. Nearly 10 microradians of change have been recorded since 4:00 a.m. HST at tiltmeters near Sand Hill and Uēkahuna bluff. Both of these tiltmeters have shown highly variable directions and rates of tilt, typical of shallow crack growth that can precede either an eruption or shallow intrusion. Step-wise changes in the tilt signal are likely due to the instrument being shaken by nearby earthquakes or rockfalls.  

Sulfur dioxide (SO2) gas emission rates remain low. Field measurements indicated an SO2 emission rate of approximately 70 tonnes per day on January 17, which was similar to measurements in October, November, and early December. 

Patterns of ground deformation and earthquakes since this morning indicate that pulses of magma continue to move beneath the surface of the region south-southwest of Kīlauea’s summit. HVO is closely monitoring Kīlauea volcano, watching for any signs of accelerated rates of earthquakes or ground deformation, or signs of shallowing earthquake locations, which usually precede a new outbreak of lava or propagating dike. We are also closely monitoring gas emissions and webcam imagery. 

Rift Zone Observations:  Seismicity in Kīlauea's East Rift Zone and Southwest Rift Zone remained low in the past 24 hours. 

We continue to closely monitor the summit and both rift zones. No unusual activity has been noted along the middle and lower sections of Kīlauea's East Rift Zone. Measurements from continuous gas monitoring stations downwind of Puʻuʻōʻō in the middle East Rift Zone—the site of 1983–2018 eruptive activity—have been below detection limits for SO2, indicating that SO2 emissions from Puʻuʻōʻō are negligible. 

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. 

The Hawaiian Volcano Observatory (HVO) continues to closely monitor Kīlauea volcano. 

Next Notice: HVO will issue daily Kīlauea updates. Additional messages will be issued as needed.