(BIVN) – On Sunday, October 16, the Hawaiʻi County Civil Defense agency issued its first radio message on the recent activity on Mauna Loa volcano.
“The U.S. Geological Survey’s Hawaiian Volcano Observatory reports that earthquake activity continues on Mauna Loa Volcano,” the message stated. “The Advisory alert status has not changed and Mauna Loa is not showing signs of an imminent eruption.”
Mauna Loa, the largest active volcano on Earth, continues to be in a state of heightened unrest. Scientists have measured increased earthquake activity and inflation of the summit, “most likely being driven by renewed input of magma 2-5 miles (3-8 km) beneath Mauna Loa’s summit”, the USGS said.
Mauna Loa remains at an alert level of ADVISORY.
The civil defense message referred the public to information and daily updates from the USGS Hawaiian Volcano Observatory.
“Your Civil Defense Agency is closely monitoring the situation and in coordination with the Hawaiian Volcano Observatory will notify you of any changes that may affect your safety,” the message stated.
The USGS HVO also issued an update on Sunday, reporting that monitoring data show no significant changes over the last 24 hours.
From Sunday’s Mauna Loa update by the USGS HVO:
Observations: During the past 24 hours, HVO detected 35 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.
The earthquakes and aftershocks from the morning of October 14, 2022 (HVO Information Statement) have not caused any changes in Mauna Loa monitoring data streams. Over the past 48 hours, there have over 150 aftershocks in the Pahala region. Of these, 20 were greater than M2.5 and 4 have been greater than M3.
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.