Increased earthquake activity may indicate magma accumulating south of summit caldera

Hawaiian Volcano Observatory scientists said Friday they are monitoring increased earthquake activity at Kilauea Volcano that may be indicative of magma accumulating south of the summit caldera.

“The lava lake has dropped, and the lava is going somewhere, and the seismicity is indicating it is going into the south caldera,” Janet Babb, a geologist with the U.S. Geological Survey’s Hawaiian Volcano Observatory, told West Hawaii Today Friday. “That cluster of seismicity there is suggesting that that may be where magma is.”

The summit lava lake at Kilauea Volcano dropped overnight and remained out of view from the Jaggar Museum Friday. The lava was about 165 feet below the rim of the Overlook Crater, which is located on the floor of Halemaumau Crater, as of Friday afternoon. The lava lake overflowed its rim beginning April 28, sending flows across the floor of Halemaumau Crater. By May 9, the lava lake level began to drop.

As the lava lake dropped, the inflationary trend changed to a deflationary trend centered near Halemaumau Crater. On May 13, the focus of deformation changed to the southern part of Kilauea’s summit caldera and upper Southwest Rift Zone, where rapid and localized inflationary tilt was recorded. This change was accompanied by a shift in the focus of earthquake activity from Kilauea’s summit, upper East Rift Zone, and upper Southwest Rift Zone to the southern part of Kilauea’s caldera and Upper Southwest Rift Zone.

This could suggest magma may be accumulating in an area just south of the summit caldera, the scientists said. That area is located near Puhimao Crater.

“We’re watching it closely,” said Babb. “It could be the magma just moving into that area, and that’s where it will be and never show itself, but it is possible that the magma could make its way to the surface as an eruption in that area, but we can’t tell at this time — there are different scenarios and possibilities.”

Earthquakes recorded by the observatory between Thursday and Friday in the area ranged from magnitude-0.4 to magnitude-3.2. The magnitude-3.2 temblor struck around 8:30 a.m. Friday south-southwest of the Kilauea Volcano summit and a magnitude-3.0 quake was registered in the area at 10:52 a.m.

Despite the elevated summit activity, there has been no obvious change in the eruption rate of lava from the Puu Oo vent, scientists said. In addition, few earthquakes have been recorded in the upper East Rift Zone over the past few days and no significant tilt was recorded on the north flank of Puu Oo during the past 24 hours.

Thermal webcam images also did not show any flows within the crater. Nighttime incandescence indicates the presence of lava in a collapsed pit crater to the west of the vent.

Breakouts along the June 27 lava flow remained active within 5 miles of Puu Oo Friday morning.

The U.S. Geological Survey Hawaiian Volcano Observatory on March 25 downgraded its alert level for Kilauea Volcano from a “warning” to a “watch.”