Geologists monitoring Kilauea volcano after latest eruption stops

  • HON

  • USGS photo This image of Kilauea volcano is from Wednesday, May 26, 2021.

Now that the latest eruption of Kilauea volcano has stopped, geologists are monitoring for signs that it might start up again.

Late Wednesday, the U.S. Geological Survey’s Hawaiian Volcano Observatory announced that Kilauea ceased erupting after 157 days of activity.


“This was actually one of the longer summit eruptions,” said Ken Hon, HVO scientist-in-charge, explaining while some summit eruptions can be extremely long-lived, such as the 10-year summit eruption between 2008 and 2018, “most of them are short-lived: somewhere between days and months. This one was on the longer end of those shorter eruptions.”

Although lava has now left Halema‘uma‘u Crater — with no liquid lava now present at the summit lake — Hon said the eruption could resume at any time. Presumably, he said, the magma dikes within Kilauea are still full of liquid lava that could spill to the surface in the event of a seismic disturbance.

However, Hon said there would likely be signs before such a resurgence.

“I think we would expect signs of repressurization before that happens,” he said.

Seismic activity at Kilauea had significantly reduced during the first three months of 2021, Hon said, as the summit eruption was relieving pressure at the volcano’s core. However, he said there is already some increased seismicity at the summit now that pressure is once again building.

On the other hand, Hon said that a persistent “tremor” at the summit — vibrations caused by the movement of magma — has decreased in intensity.

Although the eruptive activity at Kilauea does have a very loose inverse correlation with activity at Mauna Loa, Hon said the end of the Kilauea eruption doesn’t necessarily imply anything about changes to Mauna Loa.

Broadly, he explained, the higher the volume of lava erupted by one volcano, the less magma is built up within the other. —But he stressed that those volumes are relative over decades. The end of an eruption on one volcano does not mean an eruption at the other is imminent, Hon said, adding that Kilauea and Mauna Loa both experienced summit eruptions in 1984.

For now, Hon said HVO is monitoring rates of summit deflation and other factors to determine the subterranean movements of magma, while acknowledging that circumstances could change abruptly.


“It could start again, it could enter what we call a period of quiescence, we’ll see,” Hon said.

Email Michael Brestovansky at

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