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USGS HVO Volcanic Activity Notice — Kīlauea ORANGE/WATCH status change to YELLOW/ADVISORY

August 26, 2021

The U.S. Geological Survey’s Hawaiian Volcano Observatory is lowering the Volcano Alert Level/Aviation Color Code for Kīlauea from WATCH/ORANGE to ADVISORY/YELLOW reflecting this decrease in activity levels.

HVO/USGS Volcanic Activity Notice

Volcano: Kilauea (VNUM #332010)

Current Volcano Alert Level: ADVISORY

Current Aviation Color Code: YELLOW

Source: Hawaiian Volcano Observatory
Notice Number: 2021/H241
Location: N 19 deg 25 min W 155 deg 17 min
Elevation: 4091 ft (1247 m)
Area: Hawaii

Volcanic Activity Summary: Kīlauea volcano is not erupting. Over the past 24 hours, earthquake activity and ground deformation levels have decreased in the area beneath the southern part of Kīlauea’s summit caldera within the closed area of Hawaiʻi Volcanoes National Park. These observations indicate that the immediate potential for an eruption is diminished at this time.

The U.S. Geological Survey’s Hawaiian Volcano Observatory is lowering the Volcano Alert Level/Aviation Color Code for Kīlauea from WATCH/ORANGE to ADVISORY/YELLOW reflecting this decrease in activity levels.

Recent Observations:
[Volcanic cloud height] None.
[Other volcanic cloud information] None.
[Lava flow/dome] None.
[Ballistics] None.
[Lava flow] None.

Remarks: The earthquake swarm that began beneath the south part of Kīlauea caldera, within Hawaiʻi Volcanoes National Park, on August 23, 2021, has waned. Within the past 24 hours, only 10 earthquakes have been detected in this area. The earthquake swarm began in that region at around 4:30 p.m. HST on August 23 and continued until the morning of August 25, 2021. 478 earthquakes were detected during this swarm; the rate of earthquakes detected per hour peaked at 28 events between 7 and 8 p.m. HST on August 24. Most of the earthquakes were between magnitude 1 and 2 and occurred approximately 1-2 km (0.6-1.2 mi) below the Earth’s surface.

The earthquake swarm was accompanied by change in the rate and style of ground deformation. Ground deformation in the Kīlauea summit region has leveled off within the past 24 hours and rapid inflation near the region of Kīlauea’s south caldera is no longer being observed.

Earthquake activity and ground deformation have decreased together to levels that indicate magma is no longer moving into the region of Kīlauea’s south caldera. These changes indicate reduced potential for an eruption at this time.

Kīlauea summit sulfur dioxide (SO2) emission rates remain at very low levels that have persisted since May 2021, when the most recent summit eruption ended. Concentrations of SO2 in ambient air, measured at stations in the Kīlauea summit region, show no changes. The most recent SO2 emission rates, measured on August 12, were 50 tonnes per day, close to levels associated with the non-eruptive period from late 2018 to late 2020 (less than 50 tonnes per day). This is significantly lower than emission rates that averaged over 800 tonnes per day from mid-February to mid-April when the summit eruption of Kīlauea was ongoing.

HVO scientists will continue to monitor Kīlauea volcano closely and will issue additional messages as warranted by changing activity. Stay informed about Kīlauea by following volcano updates and tracking current monitoring data on the HVO web page ( or by signing up to receive updates by email at this site:

More Information:
Kīlauea activity summary also available by phone: (808) 967-8862
Kīlauea webcam images:
Kīlauea photos/video:
Kīlauea lava-flow maps:
Kīlauea FAQs:


Next Notice: The Hawaiian Volcano Observatory (HVO) continues to closely monitor Kīlauea's seismicity, deformation, and gas emissions for any changes in activity. HVO will now issue weekly Kīlauea updates on Tuesdays until further notice.

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Recent earthquakes in Hawaiʻi (map and list):

Explanation of Volcano Alert Levels and Aviation Color Codes:

The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawaiʻi.

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