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December 10, 2022

HVO is reducing the volcano alert level for Mauna Loa from WARNING to WATCH, reflecting the limited hazards associated with the current activity.

VO/USGS Volcanic Activity Notice

Volcano: Mauna Loa (VNUM #332020)

Current Volcano Alert Level: WATCH

Previous Volcano Alert Level: WARNING

Current Aviation Color Code: ORANGE

Issued: Saturday, December 10, 2022, 2:35 PM HST

Source: Hawaiian Volcano Observatory

Notice Number: 2022/H650

Location: N 19 deg 28 min W 155 deg 36 min

Elevation: 13681 ft (4170 m)

Area: Hawaii

Volcanic Activity Summary:

Lava eruption from fissure 3 (F3) on the Northeast Rift Zone of Mauna Loa continues but with greatly reduced lava output and volcanic gas emissions.  Most lava is confined to the vent in a small pond.  The short lava flows active about 1.5 miles (2.4 km) from the vent yesterday have stalled.  

The flow front in the Humu'ula Saddle region has stagnated 1.9 miles (3 km) from the Daniel K. Inouye Highway (Saddle Road) and is no longer a threat.   

High eruption rates will not resume based on past eruptive behavior and current behavior suggests that the eruption may end soon. However, an inflationary trend of Mauna Loa’s summit is accompanying the decreased activity and there is a small possibility that the eruption could continue at very low eruptive rates.  

For these reasons, HVO is reducing the volcano alert level from WARNING to WATCH, reflecting the limited hazards associated with the current activity. The aviation color code will remain at ORANGE, reflecting the uncertainty of continuing eruptive activity and the possibility of volcanic ash emissions. 

HVO scientists continue to closely monitor Mauna Loa and the active eruption site for any indication of changes to activity.  

The Federal Aviation Administration temporary flight restriction remains in place, extending from the surface to 1500 feet (457 meters) above ground level in the eruption area. See:   

For more information about the meaning of USGS volcano alert levels and aviation color codes, see  


Recent Observations:

[Volcanic cloud height] N/A

[Other volcanic cloud information] N/A

[Ballistics] N/A

[Lava flow/dome] N/A

[Lava flow] N/A

Hazard Analysis:

[General hazards] N/A

[Ash cloud] N/A

[Ashfall] N/A

[Lava flow/dome] N/A

[Mud flow] N/A

[Volcanic gas] N/A

[Other hazards] N/A

[Lava flow] N/A


Residents with questions about emergency response and resources should consult

Hawai‘i Volcanoes National Park has closed the Mauna Loa Road from Kīpukapuaulu and the closure extends to the summit caldera; for more information please see   

More Information:

Volcanic Hazards: 

Air quality/volcanic gas plume (fissure eruption): High levels of volcanic gas, including sulfur dioxide (SO2) , are emitted from the fissure vents. As SO2 is released from the eruption, it will react in the atmosphere with oxygen, sunlight, moisture, and other gases and particles and within hours to days, convert to fine particles. The particles scatter sunlight and cause the visible haze, known as vog (volcanic air pollution, from “volcanic smog”). Vog creates the potential for airborne health hazards to residents and visitors, damages agricultural crops and other plants, and affects livestock operations.  

Lava flows: Hawaiian lava flows generally advance slowly enough that people can avoid them. They can destroy everything in their paths, including vegetation and infrastructure—which can cut off road access and utilities. Hazards associated with active or recent lava flows include hot and glassy (sharp) surfaces that can cause severe burns, abrasions, and lacerations upon contact with unprotected or exposed skin; uneven and rough terrain can lead to falls and other injuries; hot temperatures that can cause heat exhaustion or dehydration, or in heavy rain can produce steamy ground-fog that can be acidic, severely limiting visibility and sometimes causing difficulty breathing.   

Tephra fall:  Pele's hair and other lightweight volcanic glass fragments from lava fountains and spattering will fall downwind, dusting the ground within a few hundred meters (yards) of the vent. High winds may waft lighter particles and transport them greater distances downwind.  These particles are sharp and can irritate the skin and eyes and could be respiratory health hazard. 

Secondary hazards: Lava flow advance into vegetated areas may generate secondary hazards by igniting small fires in vegetation adjacent to lava flow margins. Lava flows that cover and burn vegetation and soil also introduce the hazard of subsurface natural gas pockets igniting, which can cause methane explosions. These explosions can blast lava fragments up to several meters (yards) away and can be hazardous to observers.  

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.



Next Notice:

HVO will continue to issue a morning Daily Update on the status of Mauna Loa activity, which will be posted on the HVO web site at: HVO will no longer issue afternoon status reports. Additional notices will be issued as activity warrants. 


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Summary of volcanic hazards from eruptions:

Recent earthquakes in Hawaiʻi (map and list):

Explanation of Volcano Alert Levels and Aviation Color Codes:

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