Mauna Loa: Awareness and Outreach

Jan 16, 2018

Mauna Loa from Mauna Kea
Credit Wikimedia Commons

Mauna Loa is the largest active volcano on earth and makes up more than half of Hawai'i Island's land mass. Its last eruption was nearly 34 years ago, but over a longer time frame time. It’s erupted every 5 to 6 years with the potential to reach far flung parts of the island. As part of “Volcano Awareness Month,” scientists at Hawaiian Volcano Observatory are hosting workshops to inform the community. From Hawai'i Island, contributing reporter Sherry Bracken has more.

About two years ago, scientists raised the alert level for Mauna Loa because of increased earthquakes and deformation at the summit, although an eruption is not imminent.

Hawai'i Island's residents and visitors are used to Kīlauea's relatively slow moving lava flows, but Mauna Loa can be very different. Geologist Frank Trusdell explains what makes Mauna Loa different, using that volcano's 1950 flow as an example.

“The composition of Kīlauea and Mauna Loa eruptions are the same. What's most impressive is the amount of lava. At Kīlauea you have roughly about a meter per second. In 1950 we had a thousand meters per second. There were three lava flows during that eruption that breached the Kona highway in less than 24 hours. The first one reached the ocean in just over three hours, the next one was just over 14 hours, the final one in 18 hours."

Trusdell talks about previous Mauna Loa eruptions.

"Half of the eruptions stay in the summit. About a quarter of the eruptions happen along the northeast rift zone. In 1984, that flow posed a potential hazard for Hilo. About 20% occur along the southwest rift zone – an area from Ho'okena south to Na'alehu. Radial vents, like bicycle spokes on a wheel with the caldera being the hub, they radiate away from the summit on the north and west sides."

Scientists do not know exactly when nor where Mauna Loa might erupt, but they want the public to understand the volcano's potential.  

Scientists from Hawaiian Volcano Observatory will host open houses all about Mauna Loa at Ocean View Community Center on Wednesday, January 17 from 6 pm until 8, and at Konawaena Elementary School on Saturday, January 27, from noon until 3.