Hawaii’s Mauna Loa erupts for the first time in 38 years. What happens next?

After a 38-year period of calm—the longest in its recorded history—Hawaii’s Mauna Loa has reawakened.

At approximately 11:30 p.m. local time on Sunday, Mauna Loa, the largest active volcano in the world, began erupting. Lava oozed into Moku‘āweoweo, the bowl-like summit of the volcano, staining the blue-black sky with crimson hues. Throughout the night, the lava emerged and flowed mostly within this caldera, with a small amount spilling over the side. But as the sun rose, molten rock was spotted bleeding out of fresh cracks on the volcano’s northeastern flanks—a section of the mountain that is slowly being pulled apart.

At present, no major population centres are threatened and no evacuation orders have been issued, but the situation is rapidly evolving, and eruptions at Mauna Loa have proven unpredictable in the past. 

“There are eruptions at Mauna Loa that end in a day. There are also eruptions that go on for a long time. Really, there is just no way to know right now,” says Jackie Caplan-Auerbach, a volcano seismologist at Western Washington University.