2 Vents Continue to Spew Lava Within Halemaʻumaʻu Crater

Lava continues to fountain out of two vents within the Halemaʻumaʻu crater, one along the floor and the other along the western wall, since Kīlauea began erupting on Sept. 29.

As of this morning, October 7, 2021, All lava activity remains confined within Halemaʻumaʻu crater. Seismicity and volcanic gas emission rates remain elevated.

Over the past 24 hours, the lava lake rose approximately 3 feet with a total rise of about 105 feet since lava emerged, the US Geological Survey Hawaiian Volcano Observatory reported Thursday morning.

The total thickness of lava filling Halemaʻumaʻu is now 846 feet with a lake surface elevation of approximately 2,543 feet above sea level. The west vent continues to have the most vigorous fountain with sustained lava fountain heights of about 39 feet. The lava lake is now above the base of the vent and the fountain has built a spatter rampart around most of it. Another vent continues to be active in the southern part of the lake with lava fountain heights averaging 3 feet above the lake surface.

The lava lake is not level across the surface due to the location of the vents. According to HVO, areas closer to the west vent are about 7 feet higher in elevation compared to the north and south part of the lake and 7 feet higher than the east end of the lava lake.

Crustal foundering, a process by which cooled lava crust on the lake surface sinks into the hot underlying lake lava, is observed on the active surface of the lava lake. The active lava lake surface is perched 3-7 feet above a 66-foot ledge that extends outward to the Halemaʻumaʻu crater wall. The central island and several of the smaller eastern islets from the 2020 lava lake are now visible on the lake surface.

All the smaller islets became submerged at the beginning of the eruption, but have gradually emerged since. The central island shows a dark ring marking of cooled lava from partial submersion at the beginning of the eruption.

No unusual activity has been noted in the Kīlauea East Rift Zone. Ground deformation motion suggests that the upper East Rift Zone—between the summit and Puʻuʻōʻo—has been steadily refilling with magma over the past year. SO2 and hydrogen sulfide (H2S) emissions from Puʻuʻōʻō were below instrumental detection levels when last measured on Jan. 7, 2021.

With the ongoing eruption, sulfur dioxide (SO2) emission rates remain high, with a measured emission rate of approximately 7,000 tonnes per day on Oct. 6, 2021. Seismicity remains elevated but stable. Summit tiltmeters continue to record deflationary tilt.

This new eruption at Kīlauea’s summit is occurring within a closed area of Hawai’i Volcanoes National Park. Therefore, high levels of volcanic gas are the primary hazard of concern, as this hazard can have far-reaching effects downwind.

Large amounts of volcanic gas—primarily water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2)—are continuously released during eruptions of Kīlauea Volcano. As SO2 is released from the summit, it reacts in the atmosphere to create the visible haze known as vog (volcanic smog) that has been observed downwind of Kīlauea. Vog creates the potential for airborne health hazards to residents and visitors, damages agricultural crops and other plants, and affects livestock. For more information on gas hazards at the summit of Kīlauea, click here. Vog information can be found here.

Additional hazards include Pele’s hair and other lightweight volcanic glass fragments from the lava fountains that will fall downwind of the fissure vents and dust the ground within a few hundred yards of the vent(s). Strong winds may waft lighter particles to greater distances. Residents should minimize exposure to these volcanic particles, which can cause skin and eye irritation.