Hazard Notification System (HANS) for Volcanoes


U.S. Geological Survey
Monday, November 20, 2023, 8:55 AM HST (Monday, November 20, 2023, 18:55 UTC)

19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Activity Summary:  Kīlauea volcano is not erupting. The unrest associated with the intrusion that began in early October southwest of Kīlauea's summit, continues.  Seismic activity immediately south of Kīlauea’s caldera, which has been elevated over the last week, continues at low to moderate levels. Field observations of SO2 gas emissions collected on November 17th are the same as field observations in October.  Unrest may continue to wax and wane with changes to the input of magma into the area and eruptive activity could occur in the near future with little or no warning. No unusual activity has been noted along Kīlauea’s East Rift Zone.  

Summit Observations:  A new episode of earthquake activity began this morning Monday, November 20th, south of Halema’uma’u crater, seismicity continues at moderate rates.  Twenty five earthquakes were observed in the southern part of the caldera in the past 24 hours.

The Uēkahuna summit tiltmeter, located northwest of the caldera had a modest increase in tilt in the past 24 hours.  The Sand Hill tiltmeter, located southwest of the caldera, had moderate observable deformation in the last 24 hours. However, overall, the summit of Kīlauea remains at a high level of inflation, above the level reached prior to the most recent eruption in September 2023. 

Sulfur dioxide (SO2) emission rates remain low. Field observations found SO2 gas emmision of 100 tonnes per day on November 17th.  This is the same as an observation in October 2023. 

There is currently no sign of an imminent eruption, but eruptive activity is possible in the coming weeks or months. Increased inflation and earthquake activity (heightened unrest) are expected to precede an eruption.  The onsets of previous summit eruptions have been marked by strong swarms of earthquakes caused by the emplacement of a dike 1-2 hours before eruptions. 

The HVO information statement released on October 23, 2023, provides additional information and context related to recent unrest at Kīlauea summit: https://volcanoes.usgs.gov/hans2/view/notice/DOI-USGS-HVO-2023-10-23T22:33:18-07:00 

A map summarizing recent unrest southwest of Kilauea’s summit (activity beginning 10/4/23) is seen here: https://www.usgs.gov/maps/november-5-2023-summary-map-intrusive-activity-kilauea-volcano   


Rift Zone Observations:  Beginning in early November, a small cluster of earthquakes (4-12 earthquakes per day) began occurring along the Southwest Rift Zone. Most events have been smaller than magnitude-2 and have located in the middle of the Southwest Rift Zone, at depths of 1-3 miles (1-5 km) below sea level.  We continue to closely monitor this area. There have been several minor episodes of seismicity in the Upper East Rift zone in the past month, but no unusual activity has been noted along the rest of the East Rift Zone. Measurements from continuous gas monitoring stations downwind of Puʻuʻōʻō in the middle East Rift Zone have been below detection limits for SO2, indicating that SO2 emissions from Puʻuʻōʻō are negligible. 

Hazard Analysis:  Levels of volcanic gas (sulfur dioxide and carbon dioxide) can remain locally hazardous even though Kīlauea is no longer erupting. Sulfur dioxide (SO2) gas emissions have greatly decreased; however, local concentrations of sulfur dioxide (SO2) 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.

More Information:

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 and American Samoa.



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Summary of volcanic hazards from eruptions: https://www.usgs.gov/observatories/hvo/hazards
Recent earthquakes in Hawaiʻi (map and list): https://www.usgs.gov/observatories/hvo
Explanation of Volcano Alert Levels and Aviation Color Codes: https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes