Hawaii's Kilauea volcano resumed erupting Friday by shooting an arc of lava 100 feet (30 meters) into the air and across a section of its summit crater floor.

It was Kilauea's 31st display of molten rock since December, an appropriately high frequency for one of the world's most active volcanoes.

The north vent at the summit crater began continuously spattering in the morning, and then lava overflowed a few hours later. The vent started shooting lava fountains in the afternoon.

The eruption was contained within the summit crater, and no homes were threatened.

A few lucky residents and visitors will have a front-row view at Hawaii Volcanoes National Park. If the past is a guide, hundreds of thousands more will be watching popular livestreams made possible by three camera angles set up by the U.S. Geological Survey.

Whenever she gets word the lava is back, Park Service volunteer Janice Wei hustles to shoot photos and videos of Halemaumau Crater — which Native Hawaiian tradition says is the home to the volcano goddess Pele. She said that when the molten rock shoots high like a fountain, it sounds like a roaring jet engine or crashing ocean waves. She can feel its heat from over a mile away.

Kilauea is on Hawaii Island, the largest of the Hawaiian archipelago. It’s about 200 miles (320 kilometers) south of the state’s largest city, Honolulu, which is on Oahu.

A lower magma chamber under Halemaumau Crater is receiving magma directly from the earth’s interior at about 5 cubic yards (3.8 cubic meters) per second, said Ken Hon, scientist-in-charge at the Hawaiian Volcano Observatory.

This blows the chamber up like a balloon and forces magma into an upper chamber. From there it gets pushed above ground through cracks.

Magma has been using the same pathway to rise to the surface since December, making the initial release and subsequent episodes all part of the same eruption, Hon said.

Many have featured lava soaring into the air, in some cases more than 1,000 feet (300 meters). The fountains are generated in part because magma — which holds gases that are released as it rises — has been traveling to the surface through narrow, pipelike vents.

The expanding magma supply is capped by heavier magma that had expelled its gas at the end of the prior episode.

Eventually enough new magma accumulates to force the degassed magma off, and the magma shoots out like a Champagne bottle that was shaken before the cork was popped.

This is the fourth time in 200 years that Kilauea has shot lava fountains into the air in repeated episodes. There were more episodes the last time Kilauea followed this pattern: The eruption that began in 1983 started with 44 sessions of shooting fountains.

Those were spread out over three years, however. And the fountains emerged in a remote area, so few got to watch.

The other two occurred in 1959 and 1969.

Scientists don’t know how the current eruption will end or how it may change. In 1983 magma built enough pressure that Kilauea opened a vent at a lower elevation and started continuously leaking lava from there rather than periodically shooting out of a higher elevation.

The eruption continued in various forms for three decades and ended in 2018.

Something similar could happen again. Or the current eruption could instead stop at the summit if its magma supply peters out.

Scientists can estimate a few days or even a week ahead of time when lava is likely to emerge with the help of sensors around the volcano that detect earthquakes and minuscule changes in the angle of the ground, which indicate when magma is inflating or deflating.