Mauna Loa had not erupted since 1984—its longest quiet period in recorded history.
Summary
Heightened unrest began in mid-September 2022 as recorded by an increase in earthquakes 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 was caused by renewed input of magma into Mauna Loaʻs summit reservoir system. As the reservoir expanded it triggered 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 km) was detected by the continued increase in upward movement and extension (increase in distance) measured between GPS stations located on the ground surface.
At approximately 11:30 p.m. HST November 27, lava broke to the surface within Moku‘āweoweo, the summit caldera on Mauna Loa, for the first time in 38 years.
The eruption started within Moku‘āweoweo, in Hawai‘i Volcanoes National Park. Initial fissures fed lava flows that covered much of the caldera floor with new lava, but the eruption didn't stay in the caldera for long. Other fissures active in the early phase of the eruption spilled lava to the southwest of the summit region. HVO staff on an overflight at approximately 6:30 a.m. HST on November 28 confirmed that the summit eruption and the activity southwest of the summit had ended and by that time, fissures at high elevations on the Northeast Rift Zone within Hawai‘i Volcanoes National Park were feeding lava flows upslope of the Mauna Loa Weather Observatory.
Several lava flows traveled in a northeast and east direction. Several fissures were active initially but the activity eventually focused at fissure 3, from which the longest and largest lava flow issued. This lava flow crossed the Mauna Loa Weather Observatory Road at approximately 8 p.m. November 28.
Lava flows extended 12 miles (19 km) from the vents in a north/northeast direction before the eruption ended on December 10. Lava flows came to within 1.7 miles (2.8 kilometers) of the Daniel K. Inouye Highway (Saddle Road).
Mauna Loa had not erupted since 1984—its longest quiet period in recorded history.
Summary
Heightened unrest began in mid-September 2022 as recorded by an increase in earthquakes 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 was caused by renewed input of magma into Mauna Loaʻs summit reservoir system. As the reservoir expanded it triggered 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 km) was detected by the continued increase in upward movement and extension (increase in distance) measured between GPS stations located on the ground surface.
At approximately 11:30 p.m. HST November 27, lava broke to the surface within Moku‘āweoweo, the summit caldera on Mauna Loa, for the first time in 38 years.
The eruption started within Moku‘āweoweo, in Hawai‘i Volcanoes National Park. Initial fissures fed lava flows that covered much of the caldera floor with new lava, but the eruption didn't stay in the caldera for long. Other fissures active in the early phase of the eruption spilled lava to the southwest of the summit region. HVO staff on an overflight at approximately 6:30 a.m. HST on November 28 confirmed that the summit eruption and the activity southwest of the summit had ended and by that time, fissures at high elevations on the Northeast Rift Zone within Hawai‘i Volcanoes National Park were feeding lava flows upslope of the Mauna Loa Weather Observatory.
Several lava flows traveled in a northeast and east direction. Several fissures were active initially but the activity eventually focused at fissure 3, from which the longest and largest lava flow issued. This lava flow crossed the Mauna Loa Weather Observatory Road at approximately 8 p.m. November 28.
Lava flows extended 12 miles (19 km) from the vents in a north/northeast direction before the eruption ended on December 10. Lava flows came to within 1.7 miles (2.8 kilometers) of the Daniel K. Inouye Highway (Saddle Road).