Ka‘ū News Briefs, Saturday, Oct. 2, 2021

THE ISLAND IN THE THE LAVA LAKE at Halema'uma'u is most likely afloat and growing a small cone, according to USGS Hawaiian Volcano Observatory scientists. They report that shifts in the volcanic gas plume allowed field crews to glimpse at the surface of the main island that formed during the last eruption. 
   "The island appears to be blanketed with a new coating of spatter and tephra from nearby fissures within the lava lake, with minor overflows at the edges," reports USGS. Measurements by field crews indicated that the highest point on the island was 8 m (26 ft) higher than it was earlier this month; since it is unlikely that the deposit of new spatter and tephra is actually this thick, the measurements seem to indicate the island has lifted up and is floating within the lava lake once again, reports USGS. 

    The island floats on a lake full of lava.  The infusion of the crater was rapid when the eruption began on Wednesday afternoon.          

    The lake reached 60 ft. in depth within a few hours, according to USGS. The infusion slowed and steadied to about 100 to 200 cubic meters a second, similar to the rate of the 2018 eruption.

    USGS reports that in contrast, the Pu'u O'o  eruption on the Hilo side of Volcano, put out three to five cubic meters of lava per second over its life between 1983 and 2018.

    On Saturday evening, USGS reported at least three fountaining sources in Halema'uma'i crater. Spatter from the fountain near the southeast edge of the island in the center of the lava lake (that formed during the December 2020-May 2021 eruption) is constructing a small cone on the island.
 

With permission from Hawai‘i Volcanoes National Park, Hawaiian Volcano Observatory scientists continue to monitor  the ongoing eruption within Halema‘uma‘u, at Kīlauea's summit. As  of Saturday evening, no significant changes occurred  over the past 24 hours. When HVO geologists are not in the field, webcameras, such as one pictured here, allow HVO staff and the public to monitor the eruption remotely. Kīlauea summit webcams are available here. USGS photo by L. DeSmither.

Saturday evening view of the lava lake and floating island at Halema'uma'u.  USGS photo by L. DeSmither.

   Lava continued to erupt from multiple vents on the base and west wall of Halemaʻumaʻu Saturday evening. Kīlauea summit sulfur dioxide (SO2) emission rates remained high and were estimated at around 20,000 tonnes per day on Thursday and 12,900 tonnes per day on Friday. This is significantly lower than initial emission rates of 85,000 tonnes per day measured just after the eruption started on Wednesday afternoon. 

   USGS also reported this evening that the rate of lava lake rise has slowed since the early phase of the eruption. As of Saturday evening, in 24 hours, the lava lake surface rose approximately 4 meters (4.4 yds). In total, the lava lake surface has risen approximately 24 m (26 yds) since the eruption started. Localized and discontinuous crustal foundering continued, displaying a process by which cool lava crust on the surface of the lava lake is overridden by less-dense liquid from below causing the crust to sink into the underlying lake lava). Seismicity was stable, with few earthquakes and ongoing eruptive tremor. Summit tiltmeters continued to record slowing deflationary tilt through the past 24 hours. 

KAʻŪ HIGH CHAPTER OF HOSA: FUTURE HEALTH PROFESSIONALS is up and running for the 2020 - 2021 school year under the direction of Dr. Angela Miyashiro. She is a staff member, with a Phd in Sports Education, teaching physical education at the school. HOSA: Future Health Professionals is a nationwide, student-led organization endorsed by U.S. Department of Education and Health Science Education Division of the Association for Career and Technical Education. 

    As a Career and Technical Student Organization, HOSA thrives in Hawai'i, said Miyashiro. After becoming chartered in 2005 with 210 members representing 12 schools, Hawai'i HOSA grew to 23 Hawai'i  high schools and eight postsecondary institutions with a membership exceeding 1,200.

     Kaʻū HOSA was founded in 2016 and is growing. Every year most Kaʻū participants qualify to compete in States and a number qualify for Nationals. "Recognized internationally, it is a competitive prestigious program that creates an environment for growth towards future medical and health professions," said Miyashiro. "In addition we are incorporating a Rural Health Youth Advocacy Club. The mission is advocating for rural health to improve the health and well-being of the school and community."

SPINNER DOLPHINS OFTEN APPROACH SWIMMING HUMANS, but a new federal rule prohibits people from coming closer than 50 yards. The rule, which goes into effect Oct. 28, prohibits swimming with spinner dolphins and approaching them, even if on surfboard, paddleboard, canoe, kayak or other boat. The new rule, explained this week by  NOAA Fisheries, covers all Hawaiian waters up to two nautical miles from shore, plus the interisland waters between Maui, Lana'i and Kaho'olawe.
    According to the new rule, if spinners approach people and their marine going vessels, the humans won't be prosecuted by NOAA and its Hawai'i state partner Department of Land & Natural Resources, 
under the following conditions:

     People inadvertently coming within 50 yards of a Hawaiian spinner dolphin who are approached by a spinner dolphin, provided they make no effort to engage or pursue the animal and take immediate 
steps to move away from it;
    Vessels underway and approached by a spinner dolphin, provided they continue normal navigation and make no effort to engage or pursue the dolphin;                Vessels transiting to or from a port, harbor, or in a restricted channel to maintain safe navigation when a 50-yard distance will not allow the vessel to maintain 
safe navigation;
    Vessel operations necessary to avoid imminent and serious threats;
    Vessels that are anchored or aground and approached by a spinner dolphin, provided the vessel makes no effort to engage or pursue the dolphin;
    People or vessels conducting activities authorized through a NOAA Fisheries permit or authorization
    Government vessels and personnel conducting official duties;
    Commercial fishing vessels that incidentally “take” a spinner dolphin during normal fishing operations, provided that they operate legally according to the Marine Mammal Protection Act.

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Spinner dolphins face increasing pressure from people seeking  close interactions. Shown here: Multiple boats and dozens of people  in the water with spinner dolphins. NOAA photo

HO'OKENA IS ONE OF THE NEARSHORE WATERS WITH TIME-OUT AREAS proposed by NOAA Fisheries. The time-out periods for humans would be from 6 a.m. and 3 p.m. daily, in portions of the waters of Ho'okena, Kealakekua, Hōnaunau, and Makako Bays. Spinner dolphins use theses socialize, nurture their young, shelter from predators, and rest in preparation for nightly hunting” out at sea. These bays are essential daytime habitat, according to NOAA. Another time-out area is proposed for La Perouse Bay on Maui. Public comment on the time-out closures runs until Dec. 27.

    A NOAA report explains, "Even though spinner dolphins can simply 'swim away' from people or vessels if they are disturbed, doing so interrupts their rest. It keeps them in a state of vigilance, and forces them to expend energy to increase their swimming speed and/or change direction. This energy expenditure leads to less energy available for other important behaviors, such as hunting and nurturing their young, affecting their health and ability to feed."

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Telephoto aerial image of eruption in Halemaʻumaʻu at Kīlauea Volcano's summit taken during an overflight at approximately 7:30 a.m. HST on September 30, 2021. A series of fountains in the central portion of the lava lake are visible, as well as the prominent vent in the west wall of Halemaʻumaʻu. The island, which formed during the early phase of the December 2020-May 2021 eruption within Halemaʻumaʻu, remains above the new lava lake surface and is visible in the center of the photo. USGS image by K. Mulliken

VOLCANO WATCH REVIEWED THIS WEEK'S NEW ERUPTION IN HALEMA'UMA'U CRATER. The weekly column is written by USGS scientists and affiliates:
    Like the prior eruption that began in December 2020, this new activity is confined entirely within Halemaʻumaʻu. The new lava is continuing to fill the crater that collapsed in 2018 and is creating a new lava lake on top of the older one. Similar lava lakes frequently formed after collapse events in Halemaʻumaʻu in the 1800s. This pattern of summit collapse and subsequent lava lake filling is one that Kīlauea has exhibited in the past.
    Both the December 2020 eruption and current eruption were immediately preceded by about an hour of elevated seismicity beneath Halemaʻumaʻu. However, increased earthquake activity in the summit or upper East Rift Zone—as well as intrusions of magma beneath the summit region—provided clues of increased eruption potential prior to the eruptions.
    Following the intrusion of magma into Kīlauea’s south caldera and Southwest Rift Zone in late-August 2021, earthquake counts dropped to very low levels. Earthquake activity slightly increased on September 24, breaking the one-month-long seismically quiet period.
    A swarm of earthquakes began in the upper East Rift Zone beneath Pauahi Crater just before midnight on September 28 and alerted HVO seismologists to an increase in activity. Overnight, smaller earthquakes were recorded closer to the summit followed by a smaller swarm near Puhimau Crater on Chain of Craters road within Hawai‘i Volcanoes National Park. After a relatively quite morning on September 29, earthquake activity abruptly increased beneath Kīlauea’s summit around 2:00 p.m. About 30 minutes later the intensity, frequencies, and shallowness of earthquakes coupled with rapid changes in ground deformation patterns, indicated magma was moving upward beneath Halemaʻumaʻu.

Aerial image of eruption in Halemaʻumaʻu at Kīlauea Volcano's summit taken during  an overflight at approximately 7:30 a.m. HST on Sept. 30. USGS image by K. Mulliken

    These changes prompted the USGS Hawaiian Volcano Observatory (HVO) to issue a Volcanic Activity Notice (VAN) and Volcano Observatory Notice for Aviation (VONA), elevating Kīlauea’s Volcano Alert Level and Aviation Color Code to WATCH/ORANGE at 3:09 p.m. The change in status indicated that an eruption could be imminent and fissures opened in the floor of Halemaʻumaʻu less than 20 minutes later. A second VAN/VONA was released, raising Kīlauea’s Volcano Alert Level and Aviation Color Code to WARNING/RED to notify the public and emergency managers that a new Kīlauea summit eruption had begun.
    Summit tiltmeters began to record a higher rate of inflationary tilt during the 40 minutes preceding the start of the eruption; a total of 11 microradians at the nearest instrument. After the onset of the eruption, the tilt changed to a steady deflationary trend that is continuing.
   Immediately before lava erupted, uplift of the older, solidified crust was seen in a few webcam image frames in the area where the fissures opened. The initial fissure cut across the middle of the Halemaʻumaʻu crater floor and was followed about an hour later (around 4:40 p.m.) by a fissure with several vents on the western wall of Halemaʻumaʻu. Multiple active vents continue to feed the growing lava lake that has risen approximately 20 m (65 ft) since the eruption started. The tallest lava fountain, near the southern end of the lava lake, has been measured at sustained heights of approximately 20–25 m (65–82 ft) throughout the night and into the morning of September 30th.
    A preliminary calculation of the average eruption rate so far was approximately 120 cubic meters (4,238 cubic ft) per second resulting in a total erupted volume of roughly 10 million cubic meters (350 million cubic ft). These high eruption rates are accompanied by huge releases of volcanic gases—especially sulfur dioxide (SO2)—which is one of the primary hazards related to summit eruptions. Initial rates of SO2 emissions were measured at about 85,000 tonnes per day just after the start of the eruption.
    The opening phases of eruptions can be unpredictable before the eruptive vents stabilize and HVO staff continue to monitor the ongoing eruption for any future changes. And while it’s not possible to predict exactly how long the current eruption may last, we expect that more summit and upper rift zone eruptions are likely in the coming years as Kīlauea continues to re-pressurize and re-establish magma pathways after the 2018 eruption.
A helicopter overflight on September 30, 2021, at approximately 7:30 a.m. HST allowed for aerial visual and thermal imagery to be collected of Halema‘uma‘u crater at the summit of Kīlauea. This thermal map shows a closer view of the new lava lake within Halema‘uma‘u. The scale of the thermal map ranges from blue to red, with blue colors indicative of cooler temperatures and red colors indicative of warmer temperatures. The dimensions of the new lava lake are 980 m (1070 yd) E-W axis and 710 m (780 yd) in N-S axis. The estimated area of the lake is about 52 hectares (127 acres). USGS map by M. Patrick.