- Mauna Loa continues to be in a state of heightened unrest, with increased seismic activity and summit inflation. However, Mauna Loa is not erupting and there are no signs of an imminent eruption at this time. The volcano’s alert level remains at ADVISORY/YELLOW.
- The USGS Hawaiian Volcano Observatory began posting daily updates on Mauna Loa this week, reflecting the heightened level of unrest. The National Park Service has also closed the Mauna Loa summit backcountry until further notice.
From the USGS Hawaiian Volcano Observatory on Saturday, October 8:
Summary of activity: 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 seismic activity and summit inflation. The current unrest is most likely due to a new supply of magma 3-8 km below the summit of Mauna Loa. Monitoring data shows no significant changes over the past day and conditions remain similar to those reported last week.
Comments: Over the past 24 hours, the HVO has located more than three dozen low magnitude earthquakes (below M3.0) 2-3 miles (3-5 km) below the Mokuāʻweoweo caldera and 4- 5 miles (6-8 km) below high altitude. northwest flank of Mauna Loa. Both of these regions have historically been seismically active during times of unrest on Mauna Loa.
Global Positioning System (GPS) instruments atop and on the flanks of Mauna Loa have continued to measure inflation at high rates since mid-September. However, summit tiltmeters show no significant surface deformation over the past week.
Sulfur dioxide (SO2), hydrogen sulfide (H2S), and carbon dioxide (CO2) concentrations, as well as fumarole temperatures, remain stable at the summit and at Sulfur Cone in the upper South Rift. West. Webcam and thermal camera views showed no change in the volcanic landscape of Mauna Loa over the past week.
Narrative: Heightened unrest began in mid-September 2022 with an increase in earthquake rates below Mauna Loa’s summit (from 10-20 per day to 40-50 per day), an increase in the rate of inflation recorded by GPS stations and inflation recorded on the MOK inclinometer. The unrest is likely caused by a new influx of magma into Mauna Loa’s summit reservoir system. As the reservoir expands, it triggers small earthquakes directly below the Mokuāʻweoweo caldera and in an area just northwest of the caldera. Deeper magma entry (greater than 2 miles, 3 kilometers) is detected by the continued increase in upward motion and extension measured between GPS stations on the ground surface. Shallower magma inflow (less than 2 miles, 3 kilometers) was likely responsible for the inflation recorded on the summit tiltmeter during the last two weeks of September. The current locations of earthquakes and deformations do not necessarily mean that the next eruption will occur there. Mauna Loa remains at a high alert level of ADVISORY/YELLOW. The current increase in activity does not suggest that progress to an eruption is certain, and there is no indication that an eruption is imminent.
HVO will continue to closely monitor changes to Mauna Loa.