Mauna Loa hasn't erupted in decades, but it's anything but dormant

PUNA, HAWAII (HawaiiNewsNow) - There are two active volcanoes on the Big Island, not one.

Kilauea has gotten most of the headlines over the last several decades, including — unsurprisingly — over the last week amid ongoing activity in Puna.

And it's all those eruptions that are spurring some to wonder: Could the volcanic activity along Kilauea's south rift zone somehow trigger a simultaneous eruption of Mauna Loa?

Hawaii County Civil Defense authorities answered that question in a recent briefing, saying that Kilauea's outbreaks in Leilani Estates haven't affected activity in Mauna Loa. But they were also quick to point out that Mauna Loa is being constantly monitored, too.

In fact, the alert level for Mauna Loa was raised in 2015. And earlier this year, scientists were closely watching an inflation of the mountain.

The good news, said Hawaii County Civil Defense Administrator Talmadge Magno, is that Mauna Loa is not in imminent danger of erupting. The bad news: It's a matter of when, not if.

The last time Mauna Loa erupted was in 1984, and lava came within four miles of Hilo's city limits.

Other eruptions happened in 1935, 1942, 1950, and 1975.

In fact, the period from 1984 to today is the longest quiet period for the volcano in recorded history.

This story will be updated.

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