Activity at Kilauea volcano continues, with about 80 small earthquakes recorded at the summit and south of the caldera within a 24-hour period, according to the U.S. Geological Survey’s Hawaiian Volcano Observatory.
The earthquakes, most measuring less than magnitude 2, have been occurring at a rate of seven per hour, far lower than earlier this week when nearly 500 earthquakes were detected from Monday afternoon to Wednesday morning.
They are occurring from 0.6 of a mile to 2.5 miles below the surface, HVO said.
Additionally ground deformation activity is occurring, indicating an intrusion of magma moving beneath the surface.
However, there are no signs of an imminent eruption, such as gas being released or tremors (constant vibrations), said HVO Scientist-in-Charge Ken Hon. Even if an eruption should occur in the area, it would be well away from any roads, he added, with the only impact occurring in Hawaii Volcanoes National Park.
HVO had raised the alert level at 5:30 a.m. Tuesday to a watch (orange) from an advisory (yellow) due to an earthquake swarm within and south of the Kilauea caldera. A watch level indicates a volcano is exhibiting heightened or escalating unrest with increased potential of eruption. It can also mean that an eruption is underway but has limited hazards.
The activity started slowing down and the alert level was downgraded to an advisory Thursday morning. But at 6 p.m. Thursday the ground deformation beneath the south portion of the Kilauea summit region began increasing to the level seen earlier in the week, followed by increased earthquake activity after 8:30 p.m.
Small earthquakes were occurring at a rate of 16 per hour Thursday night to Friday morning, with a peak rate of 24 per hour just after midnight, HVO said. The seismic activity slowed to about six an hour after 5 a.m. Friday.
Despite the renewed activity, Kilauea Volcano’s alert level remained at advisory level.
As of about noon Saturday, there was no indication the earthquakes were migrating toward the surface and there had not been a change in ground deformation that would indicate the intrusive activity is moving closer to the surface.
Hon said the reason HVO scientists decided to keep it at advisory level is that an eruption was unlikely and the frequency of earthquakes had slowed.
“We’re seeing different type of earthquakes that are indicative of magma movement,” he said.
Hon said the 2018 Lower East Rift Zone eruption drained magma at the summit, so now there is re-pressurizing in the summit area and the magma is re-establishing pathways.