USGS HVO Press Release — Mauna Loa: How well do you know the volcano in your backyard?

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Hawai‘i ISLAND, Hawaii — Mauna Loa's eruptive history and current status are the topics of a talk by Frank Trusdell, U.S. Geological Survey Hawaiian Volcano Observatory geologist, on Wed., Jan. 8.

Trusdell, who has studied Mauna Loa for two decades, will present his talk about Earth's largest volcano in the Ocean View Community Center, 92-8924 Leilani Circle, in Hawaiian Ocean View Estates. This free presentation begins at 6:30 p.m.

Mauna Loa, one of Hawai‘i's most active volcanoes, has erupted 33 times since 1843—most recently in March 1984. During that 23-day-long eruption, lava flows reached to within four miles of Hilo city limits.

Mauna Loa has now been quiet for almost 30 years. As a result, many Hawai‘i residents may not be aware that it is an active volcano. But Mauna Loa will definitely erupt again and it could be in your lifetime, according to Trusdell. 

"When Mauna Loa erupts, it is capable of disrupting lives and commerce throughout the Island of Hawai‘i," he added.

During Mauna Loa's 1859 eruption, lava flows traveled from vents high on the northwest flank of the volcano and entered the ocean near Kīholo Bay, a distance of over 50 km (31 miles), in eight days. 

In 1950, lava erupted from a fissure on Mauna Loa's Southwest Rift Zone, at an elevation of almost 3,050 m (10,000 feet), reached the ocean in less than three hours. By the time this eruption ended, lava flows had crossed Highway 11 in three places, burying more than 1.6 km (1 mile) of the road and destroying about two dozen structures. 

HVO closely monitors Mauna Loa, and will notify public safety officials and emergency managers of any changes in its currently quiet status. "For now, it’s important for all Hawai‘i residents to become aware of the volcano's potential activity so that they are prepared for its next eruption," Trusdell said.

Trusdell's talk is one of many programs offered by HVO in January, Hawai‘i Island's 5th annual Volcano Awareness Month. For more information about this presentation, email or call (808) 967-8844. Additional Volcano Awareness Month events are posted on HVO's website at

Daily updates about ongoing eruptions, recent images and videos of summit and East Rift Zone volcanic activity, maps, and data about recent earthquakes in Hawaii are posted on the HVO website at

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