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December 2020 - September 2023 Summit Eruptions

After the 2018 summit collapse, Kīlauea volcano was quiet until an eruption began within Halema‘uma‘u crater on December 20, 2020, at about 9:30 p.m. HST. The eruption was one of several recent eruptions at Kīlauea's summit. 

This is an exciting time on Kīlauea Volcano because there have been several summit eruptions following the 2018 summit collapse. For information on the current eruption, see the eruption webpage: Recent Eruption | U.S. Geological Survey (

Kīlauea Volcano had maintained a low level of non-eruptive unrest since the end of the 2018 lower East Rift Zone eruption and summit collapse, which deepened Halemaʻumaʻu crater by over 500 meters (1640 feet).  Two months after the end of the 2018 eruption, the HVO monitoring network detected Deflation-Inflation events (DI-events) indicative that the shallow Halemaʻumaʻu magma reservoir, located approximately 1.6 km (1 mile) under Kīlauea caldera, still contained significant amounts of magma.  Several months after that, in March of 2019, the summit began to steadily inflate.  Beginning in September 2020, increased rates of uplift were observed by Global Positioning System (GPS) stations in Kīlauea’s upper East Rift Zone and over the past month were observed in Kīlauea’s summit region. 

On December 2, 2020, GPS stations and tiltmeters recorded a ground deformation event at Kīlauea’s summit indicative of a small dike intrusion of magma under the southern part of Kīlauea caldera. Following the intrusion, seismometers detected a notable increase in occurrence and duration of long-period seismic signals beneath Kīlauea’s summit, which are attributed to magmatic activity, beginning on December 17, 2020. 

The eruption began as fissures on the walls and lowest down-dropped block within Halemaʻumaʻu on December 20 at approximately 9:30 p.m. HST.  The water lake that had been present at the base of the crater was quickly boiled away and replaced by a lava lake.  Eventually, activity became focused at a vent on the west wall of Halemaʻumaʻu. By May, the eruption had filled Halemaʻumaʻu crater with 223 meters/732 ft of lava (equal to an elevation of approximately 741 meters/2431 ft above sea level); the last activity on the lava lake surface was observed on May 23, 2021. 

After the December 2020-May 2021 Halemaʻumaʻu eruption ended, Kīlauea summit region continued to slowly inflate. In August 2021, increased earthquake activity and patterns of ground deformation indicated that an intrusion was occurring, and magma was moving into an area south of Kīlauea caldera. However, no eruption occurred, and the shallow Halemaʻumaʻu magma reservoir continued to measure inflation. 

On September 29, 2021, earthquake activity increased abruptly beneath Halemaʻumaʻu around 2 p.m. HST, and at 3:21 p.m. a series of vents opened in the floor and walls of Halemaʻumaʻu crater, generating a lava lake. The activity was nearly “continuous,” though there were multiple occasions when lava was not flowing on the surface. During the late fall and winter of 2021–2022, the eruption would episodically pause for periods lasting from hours to days. These pauses typically occurred in conjunction with deflation-inflation (DI) events in the summit magma reservoir, as recorded by USGS Hawaiian Volcano Observatory (HVO) tiltmeters in the region. The eruption continued for over a year until lava supply to the Halemaʻumaʻu lava lake ceased on December 9, 2022.

Following a brief month without active lava, another eruption began at the base of Halema‘uma‘u crater on January 5, 2023. The eruption was brief compared to the previous two eruptions in Halemaʻumaʻu crater, lasting about three months and ending on March 7, 2023. 

In June 2023, another eruption, brief and lasting less than two weeks, occurred within Halema‘uma‘u crater. Much of the eruption was focused at vent on the southwest wall of the crater, above the crater floor.

Chronology of eruptive activity 2020-2023

  • December 20, 2020: Eruption begins, water lake boils away in 90 minutes
  • May 23, 2021: eruption ceases (active lava not visible after this date)
  • September 29, 2021, 3:21 p.m. HST: Eruption begins as a series of fissure vents to the east of the large island that formed in the December 2020-May 2021 lava lake
  • September 29, 2021, 4:43 p.m. HST: Another vent opens in the west wall of Halemaʻumaʻu crater
  • October 4, 2021: Activity becomes focused at two vents: one in the western wall of Halemaʻumaʻu and one in the south central portion of the lava lake
  • October 6, 2021: Eastern portion of lava lake begins to stagnate and form a crust
  • October 7, 2021: Activity becomes focused at single vent on the western wall of Halemaʻumaʻu
  • November 16, 2021: Lava begins to flow onto the lowest exposed down-dropped block of caldera floor that collapsed in 2018, northeast of Halemaʻumaʻu
  • December 2021 - March 2022: Eruption pauses 24 times, over time periods ranging from approximately two hours to nearly two days. During each pause, the active lava lake surface would drop
  • Late January 2022: Spatter cones appear on the solidified surface of eastern portion of the crater floor.
  • December 9, 2022: Lava supply to the Halemaʻumaʻu lava lake ceases and the eruption ends
  • January 5, 2023. 4:34 p.m. HST: Eruption in Halemaʻumaʻu begins, with vent activity focused in the east (vs previously the west) part of the crater floor
  • March 7, 2023: Eruption in Halemaʻumaʻu pauses
  • March 11, 2023: Intrusion occurs in Kīlauea summit region
  • June 7, 2023, 4:44 a.m. HST: Eruption begins in Halemaʻumaʻu
  • June 19, 2023: Eruption in Halemaʻumaʻu pauses
  • September 10, 2023, 3:13 p.m. HST: Eruption begins within Halemaʻumaʻu crater and on the down dropped block to the east in Kīlauea’s summit caldera
  • September 16, 2023, 11:15 a.m. HST: Lava spattering at the vents ceases, the eruption ends later that day. 


Color photograph of volcano summit
This image, taken from the KWcam around 11 am on May 27, 2021, shows the lava lake that partially filled Halemaʻumaʻu crater from December 2020-May 2021.. 

December 2020–May 2021 eruption in Halemaʻumaʻu crater 


  • Lava lake filled 229 meters (752 ft), to an elevation of 747 m (2450 ft) asl 

  • 41 million cubic meters (11 billion gallons) of lava erupted 

  • 112 acres (45 hectares) surface area of crater floor 

  • Filled 5% of the volume of the 2018 collapse


September 2021–December 2022 eruption in Halemaʻumaʻu crater 


  • Lava lake filled 143 m (469 ft), to an elevation of 886 m (2907 ft) asl 

  • 110.8 million cubic meters (29.3 billion gallons) of lava erupted 

  • 295 acres (119 hectares) surface area of crater floor 

  • Filled about 14% of the volume of the 2018 collapse 

Color photograph of crater floor
Geologists conducted a monitoring overflight of Kīlauea summit on the morning of December 10, 2022. They noted that the lava lake within Halemaʻumaʻu crater was mostly solidified, though incandescence was visible. USGS image by J. Bard. 


January 2023–March 2023 eruption in Halemaʻumaʻu crater 


  • Lava lake filled 13 meters (43 ft), to an elevation of 900 m (2953 ft) asl 

  • 16.5 million cubic meters (4.4 billion gallons) of lava erupted 

  • 292 acres (118 hectares) surface area of crater floor 

  • Filled about 2% of the volume of the 2018 collapse 


June 2023 eruption in Halemaʻumaʻu crater 


  • Lava lake filled 11 meters (36 ft), to an elevation of 910 m (2986 ft) asl 

  • 15.9 million cubic meters (4.2 billion gallons) of lava erupted 

  • 376 acres (152 hectares) surface area of crater floor 

  • Filled about 2% of the volume of the 2018 collapse 

September 2023 eruption in Halemaʻumaʻu crater and on the downdropped block

This is a video compilation of Kīlauea volcano's summit eruption in September 2023. The video shows clips of the eruptive vents and lava fountains as the eruption progressed from September 10-16, 2023. 
  • Lava lake filled 20 meters (66 ft), to an elevation of 930 m (3052 ft) asl 

  • 18.6 million cubic meters (4.9 billion gallons) of lava erupted 

  • 499 acres (202 hectares) surface area of crater floor 

  • Filled about 2% of the volume of the 2018 collapse 

The data plots below show rise of Halema‘uma‘u crater floor and sulfur dioxide emissions since December 2020. 


Remote image Url
Graph showing lava depth (in meters) that has filled Halema‘uma‘u crater, at Kīlauea volcano's summit, after the 2018 collapse, since December 2020. On January 8, 2021, a novel laser rangefinder was stationed at Kīlauea volcano's summit. The fixed instrument continuously measures the distance to a location on the western lava lake surface, and telemeters data to HVO in real time. The raw data has been edited for this graph, with a running mean average filter of 3600 seconds. Variations in plotted depth can occur due to laser rangefinder returns on gas rather than the lava surface.For reference, the base of Halema‘uma‘u after the 2018 collapse event is “zero” on this plot (equal to an elevation of 518 meters/1699 ft above sea level). Post-eruption analyses indicate that the December 2020–May 2021 lava lake filled the base of Halema‘uma‘u to a depth of 223 meters/732 ft (equal to an elevation of approximately 741 meters/2431 ft above sea level). The ongoing eruption is adding to that lava depth. Lava will overflow Halema‘uma‘u, onto the lowest down-dropped block, at a depth of 267 meters/876 ft (equal to an elevation of 790 meters/2592 ft above sea level).
Remote image Url
Sulfur dioxide (SO2) emission rates measured using an upward-looking ultraviolet spectrometer. These data are collected by traversing the gas plume in a vehicle or helicopter, downwind of Halema‘uma‘u, generally within and/or southwest of Kīlauea caldera. Results from multiple traverses during a day are averaged to yield the emission rates shown here. Successful measurements depend on wind, weather, and staff availability. Values are preliminary and are subject to revision.


Additional resources related to the eruptions: