Mauna Loa is one of five volcanoes that form the Island of Hawaii in the U.S. state of Hawaiʻi in the Pacific Ocean.
The largest sub-aerial volcano in both mass and volume, Mauna Loa has historically been considered the largest volcano on Earth, dwarfed only by Tamu Massif.
It is an active shield volcano with relatively gentle slopes, with a volume estimated at approximately 18,000 cubic miles, although its peak is about 120 feet lower than that of its neighbor, Mauna Kea.
Lava eruptions from Mauna Loa are silica-poor and very fluid, and they tend to be non-explosive.
Location: Island of Hawai‘i
Latitude: 19.475° N
Longitude: 155.608° W
Elevation: 4,169 (m) 13,679 (f)
Volcano type: Shield
Most recent eruption: March 24-April 15, 1984
Nearby towns: Hilo, Waikōloa, Ocean View, Captain Cook, Miloli‘i, Nā‘ālehu, Pāhala
Threat Potential: Very High
USGS 2018 Reports
HAWAIIAN VOLCANO OBSERVATORY MONTHLY UPDATE
U.S. Geological Survey
Sunday, August 5, 2018, 12:48 PM HST (Sunday, August 5, 2018, 22:48 UTC)
MAUNA LOA VOLCANO (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
Over the past month, earthquake activity at Mauna Loa increased slightly over the previous six months. Clusters of small earthquakes have been recorded beneath the summit caldera, upper west flank, upper Southwest Rift Zone and southeast flank but these have been minor and short-lived. Elevated earthquake counts beneath the southeast flank are in part due to strong deflation at Kīlauea volcano’s summit during July.
HVO deformation monitoring instruments on Mauna Loa have also shown changes related to ongoing strong deflation of the Kīlauea summit. There is no clear evidence of resumed magma recharge into the shallow reservoir.
HVO will continue to monitor the volcano closely.
Background: Mauna Loa is the largest active volcano on Earth. Eruptions typically start at the summit and, within minutes to months of eruption onset, about half of the eruptions migrate into either the Northeast or Southwest Rift Zones. Since 1843, the volcano has erupted 33 times with intervals between eruptions ranging from months to decades. Mauna Loa last erupted 34 years ago, in 1984.
Mauna Loa eruptions tend to produce voluminous, fast-moving lava flows that can impact communities on the east and west sides of the Island of Hawai`i. Since the mid-19th century, the city of Hilo in east Hawai’i has been threatened by seven Mauna Loa lava flows. Mauna Loa lava flows have reached the south and west coasts of the island eight times: 1859, 1868, 1887, 1926, 1919, and three times in 1950.
From 2014 through much of 2017, HVO seismic stations recorded variable, but overall elevated rates of shallow, small-magnitude earthquakes beneath Mauna Loa’s summit, upper Southwest Rift Zone, and west flank. During that same time period, HVO measured ground deformation consistent with input of magma into the volcano’s shallow magma storage system.
This notice contains additional volcanoes not displayed: Hualalai (NORMAL/GREEN), Mauna Kea (NORMAL/GREEN), Haleakala (NORMAL/GREEN), Lo`ihi (UNASSIGNED/UNASSIGNED).
Subscribe to these messages: https://volcanoes.usgs.gov/vns2/
Definitions of terms used in update: https://volcanoes.usgs.gov/volcanoes/kilauea/extra/definitions.pdf
Overview of Kīlauea summit (Halemaʻumaʻu) and East Rift Zone (Puʻu ʻŌʻō ) eruptions:
Summary of volcanic hazards from Kīlauea eruptions:
Recent Earthquakes in Hawai’i (map and list):
Explanation of Volcano Alert Levels and Aviation Color Codes:
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 Hawai`i.