Kaʻū News Briefs Oct. 17, 2024

Puhimau Pit Crater in Hawai'i Volcanoes National Park.  NPS Photo by A. LaValle

THE INTENSE SEISMICITY AND GROUND DEFORMATION along the East Rift Zone of Kīlauea in the past couple of months is interpreted to indicate intrusion of magma. This has drawn USGS Hawaiian Volcano scientists and affiliates to write this week's Volcano Watch column about Potential long-term outcomes of recent intrusions in Kilauea East Rift Zone:

    Some of this magma can leak to the surface in eruptions, but there are less likely long-term consequences that have historical analogues. 

     The eruption in and near Nāpau Crater on September 15–20 is an example of a brief eruption in this area. If a longer and larger eruption were to occur, such as at Maunaulu (1969-1974), most lava flows would head south from their vents because of the topography. Some, however, could be trapped within craters, as at Nāpau, partly or completely filling them.

    This part of the rift zone is popularly known as the Chain of Craters. Geologically, all the craters are pit craters, which form solely by collapse of the ground surface without accompanying eruption at the site. Probably all the pit craters are younger than the 15th century.
    Before about 1900, 16 pit craters dimpled the surface from Luamanu to Nāpau. Some of the craters coalesced, so there are more craters than crater names; Hiʻiaka had two craters, Pauahi three; ʻAlae two, and Makaopuhi two. Another crater, Devil's Throat, formed around 1900.
    Beginning in the 1960s and continuing to the early 1980s, this area erupted numerous times. Seven craters were partly filled (Luamanu, Hiʻiaka, Pauahi, and Nāpau) or completely filled (Aloʻi, ʻAlae, and the deepest pit in Makaopuhi). Today, the upper East Rift Zone is defined by some to end at Maunaulu, a shield that grew in 1969-1974 between now-filled Aloʻi and ʻAlae Craters.
    The Chain of Craters is the only section of the East Rift Zone and its submarine extension, the Puna Ridge, that contains pit craters. This probably relates to the proximity of the Chain of Craters to the summit of Kīlauea, where magma where magma rises from the mantle. It stands to reason that such proximity leads to more intrusions than elsewhere along the rift zone. The infrequent lateral draining of such intrusions is the likely explanation of how pit craters form.

Chain of Craters within Hawaiʻi Volcanoes National Park before 1969, when several craters were partly or completely filled with lava. Now the Chain of Craters Road turns south, away from its pre-1969 route, between Pauahi and ʻAloʻi, a pit crater buried in 1969 by Maunaulu lava flows. The junction with the Hilina Pali Road is essentially at Devil's Throat. USGS map

    The recent intrusions along the Chain of Craters could have three very different outcomes. Repeated intrusions might spawn eruptions that could bypass the craters completely, or partly or completely fill one or more craters. Another possibility is that underground draining of one of the intrusions could lead to formation of a new pit crater. One or more eruptions seem far more likely (such as the recent Nāpau eruption), but collapse to form a new pit crater happened at least 17 times in the past 550 years and so is not a rare occurrence.
    History suggests another potential effect that could accompany continued intrusions in the East Rift Zone is seismicity beneath the south flank of Kīlauea. Kīlauea volcano is always in a constant state of balance between extension of the south flank due to pressure beneath the summit of the volcano and

intrusion of magma along the rift zones. At times, the flank becomes loaded like a spring and even the relatively small force of an intrusion can trigger an earthquake.
    The largest recorded earthquake beneath Kīlauea's south flank happened in 1975. On November 29, 1975, a deadly magnitude 7.7 earthquake, the largest on the island since 1868, struck the south flank. It unleashed a tsunami that killed two campers and many horses at Halapē, and the south flank of Kīlauea moved several meters southward and downward. We don't know what led directly to this earthquake, but following, as it did, about 15 years of repeated intrusions along the Chain of Craters, a relationship with these intrusions is a possible interpretation. Current conditions provide an excellent opportunity to better understand the generation of south flank earthquakes.
    All of these extreme scenarios—a new pit crater or seaward movement of the south flank— are less likely than one or more eruptions. Continued close monitoring of the Chain of Craters area may provide clues down the road.
    A holistic, historically based approach to studying Kīlauea helps us appreciate what can happen in the long run. Evaluation of the past activity of the volcano, no matter how imperfect known, can influence our thoughts about what could happen. Even with this approach, though, we must remind ourselves that there are no facts about the future.

Volcano Activity Updates
    Kīlauea is not erupting. Its USGS Volcano Alert level is ADVISORY.
    Over the past week, about 30 earthquakes were located in Kīlauea summit region, and about 100 were located in the upper-to-middle East Rift Zone. Ground deformation rates have greatly decreased since the September 15-20 middle East Rift Zone eruption, but data show that magma is continuing to move at a low rate from the summit to the middle East Rift Zone. Future intrusive episodes and eruptions could occur with continued magma supply. The most recent measurement of sulfur dioxide (SO2) emission rate at the summit was 60 tonnes per day on September 17, 2024, and SO2 emissions were not detected at downwind of the eruption site on Monday, September 23.
    Mauna Loa is not erupting. Its USGS Volcano Alert Level is at NORMAL.
    No earthquakes were reported felt in the Hawaiian Islands during the past week.
    HVO continues to closely monitor Kīlauea and Mauna Loa.

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MALAMA 'AINA COMPOSTABLES introduces the public to its Zero Waste business run by Kaʻū High School students through an EPA REO Grant Program. The event is on Saturday, Nov. 2 10:30 a.m. to 2:30 p.m. at the O.K.K. Market in Na'alehu.
    This will be the students' first community collection event focusing on cardboard & Hi-5 resources. "The materials collected will be reused, repurposed and most importantly diverted from the community's landfill," says the statement from the students.
    Participants who contribute will also have the opportunity to win free swag.
    The EPA REO Grant Program is a three year, $1.5 million, youth-led initiative designed to empower students to take an active role in environmental stewardship. Throughout the year, students participate in running a Zero Waste business out of Kaʻū High School, focusing on increasing recycling
rates and reducing waste going into Hawaiʻi's landfill.
    Youth advocates will organize cardboard shredding demos, community outreach and educational presentations throughout the event. There will be a hula performance, games and music provided by a local DJ.
    "Community members are more than welcome to drop off or stay and hangout with us throughout the day."

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Jennifer Zelko-Schlueter

KU'IKAHI MEDIATION CENTER AND HAWAI'I COUNTY BAR ASSOCIATION invite the public
to their 19th Annual Recognition Dinner and Auction on Sunday, Nov. 17 at Hilo Hawaiian Hotel's Moku'ola Ballroom. Ku'ikahi is giving the 'Peacemaker Award' to Jennifer Zelko-Schlueter, Director of Government and Community Relations at Hawaiian Electric. The HCBA is giving its 'Meritorious Service Award' to the Honorable M. Kanani Laubach, Deputy Chief Judge of the District Court of the Third Circuit.
   The evening kicks off with no-host cocktails, silent auction, and live music at 5 p.m., followed by dinner and program at 6 p.m. The buffet features carved slow roasted prime rib of beef with au jus and creamy horseradish, furikake salmon with teriyaki sauce and wasabi aioli, hoisin glazed roast chicken, grilled shrimp with chimichurri sauce, and vegan tofu katsu. Also served are Caesar salad, penne pasta salad, sautéed seasonal vegetables, steamed rice, dinner rolls, dessert, and iced tea, hot tea, and coffee.

Judge Kanani Laubach

.   Lincoln Ashida emcees the gala event and acts as live auctioneer. Items up for bid in the silent and live auctions include gift certificates for rounds of golf, outdoor excursions, overnight stays, and dining experiences; artwork and gift baskets; fine wines, orchids, and much more.   

    Founded in 1983, Ku'ikahi has been "Finding Solutions, Growing Peace" for 41 years. This fundraiser provides a significant portion of the funds that Ku'ikahi needs to provide free and low-cost dispute prevention and resolution services in East Hawai'i.   "Our mission is to empower people to come together—to talk and to listen, to explore options, and to find their own best solutions," said Ku'ikahi president Shaunda Liu Makaimoku. "Your participation makes this mission a reality. Come celebrate 41 years of peacemaking with us!"
    Tickets are $125 per person (of which $50 is tax deductible) and are available from Ku'ikahi Mediation Center in The Hilo Lagoon Centre at 101 Aupuni Street, Suite PH 1014 B-2. Reserved tables of 8 are available to Platinum, Gold, Silver, and Bronze Sponsors. To purchase tickets or table sponsorships online, use the BUY buttons on https://hawaiimediation.org/recognition2024/. Or contact Shelby at (808) 935-7844 ext. 3 or shelby@hawaiimediation.org.

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5,000 in the mail, 2,500 on the street.