Alert Level: NORMAL, Color Code: GREEN 2025-12-04 20:25:42 UTC
HAWAIIAN VOLCANO OBSERVATORY MONTHLY UPDATE
U.S. Geological Survey
Thursday, December 4, 2025, 10:25 AM HST (Thursday, December 4, 2025, 20:25 UTC)
MAUNA LOA (VNUM #332020)
19°28'30" N 155°36'29" W, Summit Elevation 13681 ft (4170 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN
Mauna Loa seismicity rates returned to long term background levels in late November similar to seismicity rates during the prior months. A total of 147 M3+ and smaller earthquakes were detected beneath Mauna Loa's summit region in the November reporting period, while the prior month had 123 earthquakes. Modestly higher rates of seismicity were observed from late-October to early November with 8-16 earthquakes per day in earliest November. Recent seismicity is much lower than unrest prior to the 2022 eruption and has returned to 3-6 earthquakes per day.
Data from Global Positioning System (GPS) instruments on Mauna Loa show a slight increase in inflation beneath the summit starting in mid-November. These rates are normal as the volcano recovers from the 2022 eruption and magma replenishes the reservoir system. Recent data indicate that the center of deformation has shifted to the southern caldera region, indicating refilling of a south caldera magma chamber.
Gas and temperature data from a station on Mauna Loa's Southwest Rift Zone indicate these values are at background levels, with little change relative to previous months.
HVO continues to closely monitor Mauna Loa and will issue another update in one month, or earlier, should conditions change significantly.
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 northwest flank. Since its first well-documented eruption in 1843, the volcano has erupted 34 times with intervals between eruptions ranging from months to decades. Mauna Loa erupted most recently in 2022.
More Information:
This notice contains volcanoes not displayed here: Hualalai (NORMAL/GREEN), Haleakala (NORMAL/GREEN), Mauna Kea (NORMAL/GREEN), Kama'ehuakanaloa (UNASSIGNED/UNASSIGNED).
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.
CONTACT INFORMATION:
askHVO@usgs.gov
Subscribe to these messages: https://volcanoes.usgs.gov/vns2/
Summary of volcanic hazards from eruptions: https://www.usgs.gov/observatories/hvo/hazards
Recent earthquakes in Hawaiʻi (map and list): https://www.usgs.gov/observatories/hvo
Explanation of Volcano Alert Levels and Aviation Color Codes: https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes
