Prepare: Mauna Loa Resources
By Mauna Loa
Mauna Loa is Earth's largest active volcano and covers just over half of the Island of Hawaiʻi. It erupted most recently in 2022 and it will erupt again. This page provides resources to help you understand Mauna Loa eruption hazards and develop an emergency plan.
Hawaiʻi Volcanoes National Park Information:
https://www.nps.gov/havo/index.htm
County of Hawaiʻi Civil Defense Agency:
https://hawaii-county-volcano-hazards-hawaiicountygis.hub.arcgis.com/
What can you do before a future Mauna Loa eruption?
Learn the Hazards
Media

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Hazards associated with Mauna Loa eruptions include:
- Large and fast-moving lava flows
- Volcanic air pollution (VOG)
- Fine rock particles downwind
- Damaging earthquakes
- Ground cracks and fissures
- Local tsunami in coastal areas
Learn more on the HVO volcanic hazards webpage: https://www.usgs.gov/observatories/hvo/hazards
See the geonarrative: Mauna Loa: Preparing for the next eruption of Earth's largest active volcano.
Prepare
- Assess how a Mauna Loa eruption could potentially impact you based on where you and your family live, work, and commute.
- Identify which Mauna Loa lava flow inundation zone and lava flow hazard zone you live in: https://hawaii-county-volcano-hazards-hawaiicountygis.hub.arcgis.com/
- Gather emergency supplies and important documents. Create an emergency plan and share it with your friends and family. More information at: https://www.ready.gov/plan
Stay Informed
Official sources of information:
- USGS Hawaiian Volcano Observatory - subscribe to receive message about volcanic activity in Hawaii via the USGS Volcano Notification Service: https://volcanoes.usgs.gov/vns2/
- County of Hawaiʻi Civil Defense Agency - subscribe to receive County of Hawaiʻi Alerts and Notifications: https://member.everbridge.net/index/371914103062563#/signup
What can you do during a future Mauna Loa eruption?
- Get information from official sources
- Implement the emergency plan that you and your family have developed
- Heed County of Hawaiʻi guidance and evacuate if necessary
Mauna Loa reference maps
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This map shows the response time people can expect based on Mauna Loa eruptions over the past 200 years. Different sectors around Mauna Loa are colored according to how quickly lava flows can reach populated areas. The warmer the color, the more quickly the flows travel. Mauna Loa lava flows over the past 200 years are shown in gray, and the numbers along the coastline indicate lava travel times to the ocean after the vent(s) opened. Large, bold numbers record the average effusion rates for the different parts of the volcano in millions of cubic meters per day (Mm3/d).
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Media
Map showing the subaerial extents of historical lava flows from Mauna Loa. Lava flow hazard zones and districts of the County of Hawai‘i are also depicted.
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Media
Slope map of Mauna Loa, including lava flows erupted since 1823 (gray), showing the approximate number of hours or days it took for a flow to advance from the vent location to the ocean or maximum reach of a flow. One flow that moved down the steep slopes on west flank of Mauna Loa reached the ocean in as little as 3 hours after the vent started erupting in 1950. The bold numbers (for example, 12Mm3/d) are the average rates of lava effusion (outpouring of lava) in millions of cubic meters per day. Note the west flank has the steepest slopes (red-orange areas), shortest distance from vent to the ocean, and the highest average rate of effusion during eruptions, resulting in precious little time for warning residents during an eruption from the Southwest Rift Zone of Mauna Loa.
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Related
March 10, 2021—Mauna Loa eruption response times
March 10, 2021—Mauna Loa eruption response times over the past 200 years
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Map of post-1823 lava flows erupted from Mauna Loa
Slope map of Mauna Loa, including lava flows erupted since 1823 (gray), showing the approximate number of hours or days it took for a flow to advance from the vent location to the ocean or maximum reach of a flow.
Map of lava flows that have erupted on Mauna Loa Volcano — 1843-1985
Map of lava flows that have erupted on Mauna Loa Volcano from 1843-1984.
Lava inundation zone maps for Mauna Loa, Island of Hawaiʻi, Hawaii
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Geologic map of the northeast flank of Mauna Loa volcano, Island of Hawai'i, Hawaii
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Related
March 10, 2021—Mauna Loa eruption response times
March 10, 2021—Mauna Loa eruption response times over the past 200 years
Geologic map of the southern flank of Mauna Loa Volcano, Island of Hawai‘i, Hawaii
On the Island of Hawaiʻi, Mauna Loa, the largest volcano on Earth, has erupted 33 times since written descriptions became available in 1832. Some eruptions began with only brief seismic unrest, whereas others followed several months to a year of increased seismicity. Once underway, its eruptions can produce lava flows that may reach the sea in less than 24 hours, severing roads and...
Geologic map of the central-southeast flank of Mauna Loa Volcano, Island of Hawaii, Hawaii
Mauna Loa, the largest volcano on Earth, has erupted 33 times since written descriptions became available in 1832. Some eruptions began with only brief seismic unrest, while others followed several months to a year of increased seismicity. Once underway, its eruptions can produce lava flows that may reach the sea in less than 24 hours, severing roads and utilities. For example, lava...
Map of post-1823 lava flows erupted from Mauna Loa
Slope map of Mauna Loa, including lava flows erupted since 1823 (gray), showing the approximate number of hours or days it took for a flow to advance from the vent location to the ocean or maximum reach of a flow.
Map of lava flows that have erupted on Mauna Loa Volcano — 1843-1985
Map of lava flows that have erupted on Mauna Loa Volcano from 1843-1984.
Lava inundation zone maps for Mauna Loa, Island of Hawaiʻi, Hawaii
Lava flows from Mauna Loa volcano, on the Island of Hawaiʻi, constitute a significant hazard to people and property. This report addresses those lava flow hazards, mapping 18 potential lava inundation zones on the island.
Geologic map of the northeast flank of Mauna Loa volcano, Island of Hawai'i, Hawaii
SummaryMauna Loa, the largest volcano on Earth, has erupted 33 times since written descriptions became available in 1832. Some eruptions were preceded by only brief seismic unrest, while others followed several months to a year of increased seismicity.The majority of the eruptions of Mauna Loa began in the summit area (>12,000-ft elevation; Lockwood and Lipman, 1987); yet the Northeast...
Map showing lava inundation zones for Mauna Loa, Hawai'i
The Island of Hawai‘i is composed of five coalesced basaltic volcanoes. Lava flows constitute the greatest volcanic hazard from these volcanoes. This report is concerned with lava flow hazards on Mauna Loa, the largest of the island shield volcanoes. Hilo lies 58 km from the summit of Mauna Loa, the Kona coast 33 km, and the southernmost point of the island 61 km.Hawaiian volcanoes erupt...
The lava flow that came to Hilo—The 1880–81 eruption of Mauna Loa volcano, Island of Hawai‘i
The Mauna Loa eruption sequence of 1880–81 consists of two eruptions. The May 1880 eruption in Mokuʻāweoweo at the summit of Mauna Loa lasted just a few days and was followed 6 months later by three lava flows that issued from vents along the Northeast Rift Zone. The November 1880 eruption lasted almost a year and one of its flows nearly reached Hilo Bay.Public reaction in Hilo to the...
Authors
James P. Kauahikaua, Ben Gaddis, Ku`ulei Kanahele, Ken Hon, Valerie Wasser
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Mauna Loa on the Island Hawaiʻi is the world’s largest volcano. People residing on its flanks face many hazards that come with living on or near an active volcano, including lava flows, explosive eruptions, volcanic smog, damaging earthquakes, and local tsunami (giant seawaves). The County of Hawaiʻi (Island of Hawaiʻi) is the fastest growing County in the State of Hawaii. Its expanding...
Authors
Frank A. Trusdell
Community preparedness for lava flows from Mauna Loa and Hualālai volcanoes, Kona, Hawai'i
Lava flows from Mauna Loa and Hualālai volcanoes are a major volcanic hazard that could impact the western portion of the island of Hawai'i (e.g., Kona). The most recent eruptions of these two volcanoes to affect Kona occurred in A.D. 1950 and ca. 1800, respectively. In contrast, in eastern Hawai'i, eruptions of neighboring Kilauea volcano have occurred frequently since 1955, and...
Authors
Chris E. Gregg, Bruce F. Houghton, Douglas Paton, Donald A. Swanson, David M. Johnston