In an Aug. 22 news release, the USGS Hawaiian Volcano Observatory stated that a new lava flow, dubbed the June 27 flow for the date it began, was rapidly advancing toward residential areas near Pahoa in the Puna District of Hawaii Island. By that time, the flow had entered a pre-existing ground crack, which channeled the flow to the east. The crack eventually filled and lava emerged from its lower end, only to spill into an adjacent crack. This process was repeated several times during the following days, with some ground cracks capturing and directing the flow, while others were filled as lava advanced across them. The average advance rate for the flow during this period was about 820 feet per day.
By Sept. 4, the flow had advanced to within 0.8 mile of Kaohe Homesteads, prompting HVO to elevate the Alert Level Code from “WATCH” to “WARNING” to draw attention to the increased threat — volcanoes.usgs.gov/activity/alertsystem.
The June 27 flow filled and exited the last major crack in its path on Sept. 6, when lava turned north as it escaped the system of cracks, faults and grabens, down-dropped blocks, that had channeled its advance within Kilauea volcano’s east rift zone.
Thereafter, the flow began to move steadily forward as a surface flow, bypassing the south portion of Kaohe Homesteads. With this change in direction, however, the June 27 flow picked up speed and began to travel at about 0.25 mile per day.
The flow narrowness and rapid development of a robust tube system within subsurface cracks make the June 27 lava flow unique among the hundreds of lava flows that Puu Oo has erupted. Our best estimates suggest that the tube is transporting about 55,000 to 73,000 gallons per minute of lava to the flow. This is approximately the long-term average eruption rate for Puu Oo over its 31-plus year eruptive history.
To forecast where this lava flow could go in future days, HVO has calculated downslope paths using a digital elevation model. These paths are identified as blue lines in most of the recent maps posted on the HVO website — hvo.wr.usgs.gov/maps. Which path the flow might follow becomes more obvious as the flow advances across the Puna terrain.
By Sept. 11, the flow had veered to the northeast and was headed toward the northwest edge of Kaohe Homesteads. If the flow continues, HVO forecasts that the flow will cross Pahoa Village Road about 0.7 mile toward the center of Pahoa from the Pahoa Marketplace on or around Sept. 24 to 26.
HVO is working closely with Hawaii County Civil Defense to monitor the June 27 flow. HVO scientists are participating in community meetings in Pahoa, as well as in meetings with county and state departments to provide the best information possible during this time.
Daily Kilauea eruption updates describing conditions for the entire volcano are posted on the HVO website every morning — hvo.wr.usgs.gov/activity/kilaueastatus.php. In addition, HVO monitoring flights are conducted each Monday, Wednesday and Friday to map the flows, assess their hazards and acquire photos and infrared video. Hawaii County Civil Defense Administrator Darryl Oliveira also flies over the lava flow every morning and posts a daily update at hawaiicounty.gov/active-alerts.
The HVO and Civil Defense information is compiled into maps that are posted after each HVO overflight at hvo.wr.usgs.gov/maps. Photos and videos of the lava flow are posted at hvo.wr.usgs.gov/multimedia.
HVO’s website also offers a limited ability to view the June 27 lava flow on webcams at hvo.wr.usgs.gov/cams/region_kier.php. When conditions are clear, the distant smoke plume can usually be seen in the Puu Oo north flank camera image, although the June 27 flow front is quite far away. A mobile cam is also pointed toward the flow front and usually shows smoke during the day and glow at night from the flow front and nearby breakouts.
We encourage Puna residents to stay informed about the lava flow. We all can hope for the best, but must also plan for the worst.
Kilauea activity update
The June 27 lava flow from Puu Oo remained active on Kilauea volcano’s east rift zone. The active flow front was 9.1 miles from the vent and 0.3 mile from the eastern boundary of the Wao Kele o Puna Forest Reserve as of Sept. 11 (the time of this writing), and moving in a northeasterly direction. Within the Puu Oo crater, glow was visible above several small lava ponds and outgassing openings in the crater floor.
The summit lava lake within Halemaumau Crater produced nighttime glow visible via HVO’s webcam over the past week. The lava lake level ranged from 180 to 215 feet below the rim of the overlook crater.
There were no earthquakes in the past week reported felt on Hawaii Island.
Visit the HVO website for Volcano Watch articles and Kilauea, Mauna Loa and Hualalai activity updates, recent volcano photos and earthquakes; call 967-8862 for a Kilauea summary; email questions to askhvo@usgs.gov.