Volcano Watch — Lava consolidates but flow remains steady

The 10-year-long eruption on Kīlauea's East Rift Zone continues with little change. During the week, the lavaentries into the ocean consolidated to three main entries on the east and west edges of the Kamoamoa flow and near the west edge of the Lae`apuki flow. 

Late in the week, the amount of lava discharged into the ocean declined as the tube system became blocked near the ocean. However, this decreased discharge was not caused by reduced magma flux from the vents but by new breakouts of surface lava flows near the Chain of Craters Road.

The lava pond inside the Pu`u `O`o cone was about 260 feet below the lowest point on the rim of the cone, compared to levels of about 240 feet observed in previous weeks. The pond was very active, with low lava fountaining at the west end and spattering at the east end, where the lava flowed into the pond. The flow of lava and cooled crust across the pond from west to east was more rapid than we have seen recently.

Volcanic fume is now emitted from the Pu`u `O`o lava pond, from the 51 and 53 vents on the south and west sides of the cone, and from the two collapse pits on the western flank of Pu`u `O`o. In the past, most of the fume was emitted from the Pu`u `O`o cone and did not hug the ground. With the numerous sites where fume is now emitted, much of the fume is concentrated close to the ground, where it poses a hazard to people in the area. 

The volcanic fume is mainly water vapor (steam) and sulfur dioxide. Following heavy rains, the fume cloud appears white because of the additional water vapor, whereas the fume appears bluish when there is little water vapor in the plume. In either case, the fume contains abundant sulfur dioxide which can cause respiratory problems. The fume emitted from skylights in the tube system is mainly sulfur dioxide as well. Our field personnel carry and use gas masks to protect themselves from the fume. 

As this fume is blown away from the vent area, water and sulfur dioxide react to form sulfuric acid and minute particles, mainly of sulfate, that become the vog that reduces visibility and causes health problems, particularly on the Kona side of the island. During times when Kona winds blow, the eastern side of the island may experience vog, as well.

The plume near the vent is distinct from that formed where lava flows into the ocean. The plume at the ocean is also mainly water vapor, but also contains hydochloric acid, which irritates both skin and lungs. Some sulfur dioxide is also emitted by the lava at the ocean as gas bubbles within the lava break and release gas. However, the amount is small compared to the amount that is emitted from the Pu`u `O`o area. 

The fume, and sometimes the glow from the lava pond within Pu`u `O`o, can be seen from Glenwood at South Glenwood Road and from the top of Pu`u Huluhulu on the trail to Mauna Ulu in Hawai`i Volcanoes National Park. The active lava flows can be viewed at the end of Chain of Craters Road. Depending on the activity, all the lava may be pouring into the ocean or surface flows of pahoehoe lava may be observed. The Visitor Center in Hawai`i Volcanoes National Park provides activity updates and directions to the lava flows for visitors.