Two years ago, Kilauea Volcano’s “June 27” flow advanced to the northeast, threatening Pahoa and creating major disruptions to thousands of residents in the lower Puna District. Today, a new flow from Puu Oo is moving to the southeast along the boundary of Hawaii Volcanoes National Park and could eventually reach the ocean.
As Hawaii residents can appreciate, change is just part of the typical behavior of Kilauea’s ongoing East Rift Zone eruption.
This new lava flow, informally dubbed the “61g” flow after the eruptive episode sequence the USGS Hawaiian Volcano Observatory uses to document Puu Oo flows, began on May 24. Over the past six weeks it has advanced to the southeast without interruption. The flow has remained relatively narrow and focused, and consists mostly of pahoehoe lava, which is typical of Puu Oo flows in recent years.
Around June 23, the 61g flow reached the top of the pali (cliff) above the coastal plain and the upper boundary of the abandoned Royal Gardens subdivision, which is almost completely buried by earlier Puu Oo lava flows. As the flow continued to advance, it picked up speed on steep sections of the pali, forming impressive ‘a‘ā lava channels on the slopes.
Within a few days, the flow front reached the base of the pali and began its advance across the coastal plain. There, the flow front narrowed even more, perhaps because it was confined by nearby high ground created by earlier Puu Oo flows. This focusing of the flow probably contributed to its high advance rate on the coastal plain.
The 61g flow front initially moved across the coastal plain at a rate of up to 0.4 mile per day, which is fairly rapid compared with other Puu Oo pahoehoe flows. As of mid-day on July 7, the flow front was about 0.7 mile from the ocean, and still moving at a good clip. Given the flow’s current advance rate, lava could reach the ocean for the first time since August 2013 in the coming days or weeks. However, the flow’s advance could slow, spreading lava across the coastal plain rather than into the ocean, or it could stall.
Compared to the June 27 flow, which threatened Pahoa and nearby subdivisions, the location of the 61g lava flow presents no immediate hazard to residential areas. It is currently overrunning older Puu Oo lava flows a safe distance from the nearest homes.
Although the hazard to property has diminished, the potential hazard to people is greater now that the flow is more accessible. The opportunity to see an active lava flow is already drawing hundreds of visitors hoping for a glimpse of lava to Kilauea’s south coast.
Besides the obvious dangers of molten lava (burns, exposure to fumes), hiking to a lava flow is risky for a number of reasons, including the possibility of falling on the rough, uneven terrain, becoming dehydrated, or suffering heat exhaustion or stroke. Heat from above (the sun) and below (hot ground) can rapidly overwhelm even the strongest of hikers. Proper gear — sturdy hiking boots, long pants, gloves, sun protection — and lots of water are essential for safe hiking.
If lava reaches the sea and forms an ocean entry, new hazards will appear. In general, ocean entries are the most dangerous part of a lava flow field due to unpredictable bench collapses, explosions, and scalding steam plumes. This danger is not theoretical — several people have died near Kilauea ocean entries in years past.
To safely view the 61g flow, your best plan is to get up-to-date lava-viewing information from Hawaii Volcanoes National Park (www.nps.gov/havo/planyourvisit/lava2.htm ) and the County of Hawaii (www.hawaiicounty.gov/lava-viewing/). These agencies have outlined where and when safe lava viewing is available.
The U.S. Geological Survey offers information on viewing lava safely in an online Fact Sheet (https://pubs.usgs.gov/fs/2000/fs152-00/fs152-00.pdf). Because it was published in 2000, the map is out of date. However, the hazard information and safety tips provided in the Fact Sheet are timeless and relevant.
From home, you can track the progress of Kilauea’s lava flow through daily eruption updates and recent maps and photos posted on the USGS Hawaiian Volcano Observatory website (https://hvo.wr.usgs.gov/).
Volcano Watch is a weekly article and activity update written by U.S. Geological Survey Hawaiian Volcano Observatory scientists and affiliates.
Volcano Activity Updates
Kilauea continues to erupt at its summit and East Rift Zone. During the past week, the summit lava lake level varied between about 79-15 feet below the vent rim within Halemaumau Crater. On the East Rift Zone, the eastern Puu Oo breakout remained active, producing a lava flow (informally called the “61g flow”) that continued to advance to the southeast. As of mid-day on July 7, the flow was about 0.7 mile from the ocean. The lava flow does not pose an immediate threat to nearby communities.
Mauna Loa is not erupting. Seismicity rates remain above background levels. Deformation related to inflation of a magma reservoir beneath the summit and upper Southwest Rift Zone continues, with inflation recently occurring mainly in the southwestern part of Mauna Loa’s magma storage complex.
No earthquakes were reported felt on Hawaii Island this past week.
Visit the HVO website (https://hvo.wr.usgs.gov) for past Volcano Watch articles, Kilauea daily eruption updates, Mauna Loa weekly updates, volcano photos, recent earthquakes info, and more; call for summary updates at 967-8862 (Kilauea) or 967-8866 (Mauna Loa); email questions to askHVO@usgs.gov.
