Volcano Watch — The June 27th flow advances toward Pāhoa

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 over the following days, with some ground cracks capturing and directing the flow, while others were simply filled as the lava advanced across them. The average advance rate for the flow during this period was about 250 meters per day (820 feet per day).

By September 4, the flow had advanced to within 1.3 km (0.8 mi) of Kaohe Homesteads, prompting HVO to elevate the Alert Level Code from "WATCH" to "WARNING" to draw attention to the increased threat (http://volcanoes.usgs.gov/activity/alertsystem/).

The June 27th flow filled and exited the last major crack in its path on September 6, when lava turned north as it escaped the system of cracks, faults, and grabens (down-dropped blocks) that had channeled its advance within Kīlauea 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 27th flow picked up speed and began to travel at about 400 meters per day (0.25 miles per day).

The flow narrowness and rapid development of a robust tube system within subsurface cracks make the June 27th lava flow unique among the hundreds of lava flows that Pu‘u ‘Ō‘ō has erupted. Our best estimates suggest that the tube is transporting about 300,000–400,000 cubic meters per day (55,000–73,000 gallons per minute) of lava to the flow. This is approximately the long-term average eruption rate for Pu‘u ‘Ō‘ō 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 (DEM). These paths are identified as blue lines in most of the recent maps posted on the HVO website (http://hvo.wr.usgs.gov/maps/). Which path the flow might follow becomes more obvious as the flow advances across the Puna terrain.

By September 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 Pāhoa Village Road about 1.2 km (0.7 mi) toward the center of Pāhoa from the Pāhoa Marketplace on or around September 24-26.

HVO is working closely with Hawai‘i County Civil Defense (HCCD) to monitor the June 27th flow. HVO scientists are participating in public Community Meetings in Pāhoa, as well as in meetings with County and State Departments to provide the best information possible during this time.

Daily Kīlauea eruption updates describing conditions for the entire volcano are posted on the HVO website every morning (http://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. HCCD Administrator Darryl Oliveira also flies over the lava flow every morning and posts a daily update at http://www.hawaiicounty.gov/active-alerts/.

The HVO and HCCD information is compiled into maps that are posted after each HVO overflight at http://hvo.wr.usgs.gov/maps/. Photos and videos of the lava flow are posted at http://hvo.wr.usgs.gov/multimedia/.

HVO's website also offers a limited ability to view the June 27th lava flow on webcams (http://hvo.wr.usgs.gov/cams/region_kier.php). When conditions are clear, the distant smoke plume can usually be seen in the Pu‘u ‘Ō‘ō North Flank (PNcam) image, although the June 27th flow front is quite far away. The Mobile Cam 3 (R3cam) 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.

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Volcano Activity Update

The June 27th lava flow from Pu‘u ‘Ō‘ō remained active on Kīlauea Volcano's East Rift Zone. The active flow front was 14.6 km (9.1 mi) from the vent and 0.5 km (0.3 mi) from the east boundary of the Wao Kele o Puna Forest Reserve as of September 11 (the time of this writing), and moving in a northeasterly direction. Within the Pu‘u ‘Ō‘ō crater, glow was visible above several small lava ponds and outgassing openings in the crater floor.

The summit lava lake within Halema‘uma‘u Crater produced nighttime glow that was visible via HVO's webcam over the past week. The lava lake level ranged from 55 to 65 m (180–215 ft) below the rim of the Overlook crater.

There were no earthquakes in the past week reported felt on the Island of Hawai‘i.