HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE U.S. Geological Survey Wednesday, October 12, 2022

HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Wednesday, October 12, 2022, 6:08 AM HST (Wednesday, October 12, 2022, 16:08 UTC)

MAUNA LOA (VNUM #332020)
19°28’30” N 155°36’29” W, Summit Elevation 13681 ft (4170 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Activity Summary: Mauna Loa is not erupting and there are no signs of an imminent eruption at this time. However, Mauna Loa continues to be in a state of heightened unrest as indicated by increased earthquake activity and inflation of the summit. The current unrest is most likely being driven by renewed input of magma 2-5 miles (3-8 km) beneath Mauna Loa’s summit. Monitoring data show no significant changes in the past day and conditions remain similar to those reported for the past week.

Observations: During the past 24 hours, HVO detected 65 small-magnitude (below M3.0) earthquakes 2-3 miles (3-5 km) below Mokuāʻweoweo caldera and 4-5 miles (6-8 km) beneath the upper-elevation northwest flank of Mauna Loa. Both of these regions have historically been seismically active during periods of unrest on Mauna Loa.

Global Positioning System (GPS) instruments at the summit and on the flanks of Mauna Loa continue to measure inflation at rates elevated since mid-September. However, tiltmeters at the summit are not showing significant surface deformation over the past week.

Concentrations of sulfur dioxide (SO₂), hydrogen sulfide (H₂S), and carbon dioxide (CO₂), as well as fumarole temperatures, remain stable at the summit and at Sulphur Cone on the upper Southwest Rift Zone. Webcam and thermal camera views have shown no changes to the volcanic landscape on Mauna Loa over the past week.

Narrative: Heightened unrest began in mid-September 2022 with increased earthquake rates below Mauna Loa summit (from 10-20 per day to 40-50 per day), an increased rate of inflation recorded by GPS stations, and inflation recorded on the MOK tiltmeter. The unrest is likely caused by renewed input of magma into Mauna Loa’s summit reservoir system. As the reservoir expands it is triggering small earthquakes directly beneath Mokuāʻweoweo caldera and in a region just to the northwest of the caldera. Deeper magma input (greater than 2 miles, 3 kilometers) is detected by the continued increase in upward movement and extension measured between GPS stations located on the ground surface. Shallower magma input (less than 2 miles, 3 kilometers) was likely responsible for inflation recorded on the summit tiltmeter during the last two weeks of September. The current locations of earthquakes and deformation do not necessarily mean that the next eruption will occur there. Mauna Loa remains at an elevated alert level of ADVISORY/YELLOW. The current increase in activity does not suggest that a progression to an eruption is certain, and there are no indications that an eruption is imminent.

HVO will continue to closely monitor Mauna Loa for changes.

HVO will continue to issue daily Mauna Loa Volcano updates until further notice. Additional messages will be issued as needed.

For more information on current monitoring of Mauna Loa volcano, see: https://www.usgs.gov/volcanoes/mauna-loa/monitoring.

Related Volcano Watch from October 6, 2022: https://www.usgs.gov/observatories/hvo/news/volcano-watch-recent-events-mauna-loa-remind-us-be-prepared-quick-changes

Hawaiʻi Volcanoes National Park: https://www.nps.gov/havo/

County of Hawaiʻi Civil Defense Agency: https://hawaii-county-civil-defense-agency-hawaiicountygis.hub.arcgis.com/

Background:

Mauna Loa is the largest active volcano on our planet and covers half of the Island of Hawaiʻi. Eruptions tend to produce voluminous, fast-moving lava flows that can impact communities on the east and west sides of the Island.

Mauna Loa eruptions typically start at the summit and, within minutes to months of eruption onset, can migrate into either the Northeast or Southwest Rift Zone, or radial vents on the north flank. Since its first well-documented eruption in 1843, the volcano has erupted 33 times with intervals between eruptions ranging from months to decades. Mauna Loa last erupted in 1984.