Will Mauna Loa erupt again? Scientists say it's a matter of when — not if

Will Mauna Loa erupt again? Scientists say it's a matter of when — not if

MAUNA LOA, HAWAII (HawaiiNewsNow) - According to geologists, there is no way to determine exactly when Hawaii Island's Mauna Loa volcano will erupt next.

Because of this, Community Forums, a local nonprofit, is sponsoring an update on activity in Mauna Loa and Hualalai volcanoes.

The event will be from 6 p.m. to 8 p.m. Thursday, at West Hawaii Civic Center Council Chambers.

The primary speaker at the event will be Frank Trusdell from the Hawaiian Volcano Observatory, who has studied Hawaii Island volcanoes for decades.

"The holy grail of volcanology is to be able to forecast a date and time in the future when a volcanic eruption will occur," Trusdell said. "And we have a long way to go to be able to forecast that in the future."

With the alert level for Mauna Loa being upgraded in 2015 because of increasing seismic and inflation activity, researchers and community leaders say it's important to understand what the potential for eruptions might be.

"The reason why we are talking about Mauna Loa now is because it was in a state of slumber and now we have slightly elevated earthquakes and we can see the volcano changing it's shape due to the influx of magma," Trusdell said.

Trusdell also says that while an eruption isn't imminent, Mauna Loa is still an active volcano that needs to be monitored.

Other speakers at Thursday's forum include Talmadge Magno, the administrator for Hawaii County Civil Defense, who will discuss disaster preparedness plans and Jay Ignacio, President of Hawaii Electric Light Company, who will talk about how HECO preparation measures before and after an eruption.

Past Eruptions

According to the United states Geological Survey website, on Nov. 21, 1935, an eruption began on Mauna Loa and quickly migrated down its Northeast Rift Zone.

On Dec. 27, military planes dropped bombs near the eruptive vent in an attempt to divert the flows. Military leaders thought the operation was a success, but because the eruption ended just six days later, the efficacy of disrupting lava channels with bombs or other explosives remains disputed.

1935 Eruption Threatened Hilo
1935 Eruption Threatened Hilo

Mauna Loa's "secret" eruption began on April 26, 1942.

With World War II underway, night time blackouts were imposed on Hawaii. American officials feared that if the eruption were publicized, the Japanese military could use the bright glow of lava at night to guide warplanes to Hawaii.

The eruption began on the western rim of Mauna Loa's summit, but then migrated down the volcano's Northeast Rift Zone.

By the time the eruption ended on May 9, lava had reached to within seven miles of the upper Waiakea Uka area of Hilo.

1942 Mauna Loa lava flow
1942 Mauna Loa lava flow

A 1950 eruption lasted for 23 days.

It erupted 492 million cubic yards of lava, the largest outpouring of lava from the southwest rift zone of Mauna Loa since written records have been kept.

Flows from this eruption made their way to the sea quickly. The Honokua flow covered the 15-mile journey from the vent to the ocean, in less than three hours.

1984 eruption
1984 eruption

Following 25 years of slumber, Mauna Loa awoke with a spectacular, but short-lived, eruption just before midnight on July 5, 1975.

Mauna Loa's most recent eruption occurred from March 24 to April 15, 1984.

The eruption began suddenly, following a three year period of slowly increasing earthquake activity beneath the volcano that included a swarm of earthquakes three to nine miles deep in mid-September 1983.

The earthquakes reached a maximum frequency just after a 6.6-magnitude earthquake. The 1984 eruption came within four miles of the city limits of Hilo.

Mauna Loa hasn't erupted since 1984, making it the volcano's longest quiet period in recorded history.

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