Kaʻū News Briefs, Thursday, June 29, 2023

A decade ago, the Independence Day Parade travels past Na'alehu Theatre, which was torn down this year. For 2023, the
 parade will be this Saturday, July 1 at 11 a.m., sponsored by O Ka'u Kakou. Photo by William Neal

THE U.S SUPREME COURT STRUCK DOWN RACE-BASED AFFIRMATIVE ACTION on Thursday. Hawai'i's Senator Mazie Hirono released the following statement on the Supreme Court’s decision, which rules that affirmative action policies at University of North Carolina and Harvard University are unconstitutional:
   “Affirmative action policies have helped colleges and universities across our country cultivate more diverse student bodies," wrote Hirono. "These commonsense policies recognize that diversity on campuses

The Supreme Court ended affirmative action at
colleges and universities. Photo from PBS

benefits all students, and help to advance racial equity.
    “But once again, this extreme Supreme Court has taken our country backwards. Given our country’s long history of racial discrimination and the stark racial inequality that continues to this day, for Justices to focus on whether the benefits of diversity can be measured precisely is shortsighted and detached from reality.
    “Diversity of every kind makes us stronger. At a time when those on the right disavow diversity in a cynical attempt to divide us, I’ll continue working to advance diversity, equity, and justice for all.”
    In August 2022, Senator Hirono signed an amicus brief in support of UNC and Harvard’s affirmative action policies. See https://www.supremecourt.gov/DocketPDF/20/20-1199/232469/20220801161644001_RSAC%20Nos%20201199%2021707.pdf.

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TRACKING DOWN MAUNA LOA'S CARBON DIOXIDE is the subject of Volcano Watch, the weekly article and activity update written by U.S. Geological Survey Hawaiian Volcano Observatory scientists and affiliates:
    When lava poured out over the floor of Moku'āweoweo, Mauna Loa's summit caldera, late on the night of Nov. 27, 2022, it was still many hours away from infrastructure. Or most infrastructure.
    The lava eventually blocked Mauna Loa NOAA observatory access road the next day, but well before it got there, it destroyed the Hawaiian Volcano Observatory's summit gas measuring station—less than ten minutes after the eruption began.

The former gas monitoring station in Moku'āweoweo, Mauna Loa's summit caldera. Power and telemetry components of the station are to the right in the image, with solar panels. The gas sensors themselves were housed in the black box toward the lower left of the image. Note that the white, yellow, and orange discoloration of the dark ground surface is a result of volcanic gases reacting with the darker rocks. USGS photo by K. Calles

    The station measured four gases—sulfur dioxide (SO2), carbon dioxide (CO2), hydrogen sulfide (H2S), and water vapor—as well as meteorological parameters including wind speed and fumarole (small gas vent) temperature. As part of HVO's monitoring network, the station was installed to alert HVO of any changes in gas concentrations or the temperature at the site. Had the station survived, it would have given HVO a rich dataset regarding the chemistry of any eruptive gases blown toward it.

CO2 in particular can be indicative of deep magma recharge, either before or after an eruption.

    For example, at Kīlauea, a decrease in the proportion of CO2 relative to SO2 over a few months was a clue hinting at the eventual onset of Kīlauea's 2008-2018 summit eruption.

    At Mauna Loa, the NOAA observatory has a long history of measuring atmospheric CO2. Volcanic CO2 is removed from their long-term atmospheric dataset, though that removed data can in turn be used to study Mauna Loa's CO2 emissions. A study published in 2001 by a NOAA observatory scientist—using data from the 1950s through the 1990s, which covers the periods after the 1950, the 1975, and the 1984 eruptions—showed that most CO2 there has been released after each of those eruptions.

    That study also showed a small increase in CO2 emission from Mauna Loa in the 1990s, when there was no eruption. It's possible that this CO2 pulse was related to a deep magma intrusion that didn't make it to the surface.

    There was no increase in CO2 emission detected before the 2022 eruption; however, based on the 2001 NOAA study, we might expect enhanced CO2 degassing now that the eruption is over.

Given the potential for anomalous CO2 emissions before, during, and after eruptions, HVO is eager to replace the station at Mauna Loa summit as soon as possible.

An HVO gas scientist carrying portable gas sensor (yellow box) near Mauna Loa summit in June 2023. The white material on the ground in this photo is snow. USGS photo by P. Nadeau 

     However, before we can do that, we need to find a new suitable location. The previous station was on the floor of Moku'āweoweo, where we hoped that it might detect increased degassing before a new eruption, but that location clearly came with a lot of risks. The initial lava flows from the 2022 eruption destroying the station meant that we got no data from it during the ensuing two weeks of eruption.

    This time, HVO is considering placing a station on the caldera rim, which is close enough to measure CO2 emitted from the caldera during favorable wind conditions and is a much safer spot. A new station there should survive future summit activity and give us gas data throughout eruptions.

    Earlier in June, HVO gas scientists headed to Mauna Loa's summit to begin searching for locations where gas might already be leaking out of the ground. They brought with them small, portable versions of the same gas sensors that are part of larger permanent monitoring stations. Visits to other summit locations are planned for later this summer as we continue the hunt for the best spot for the new station.

    As you read this, you may be wondering how volcanic CO2 emissions like those at Mauna Loa and Kīlauea compare to other sources of CO2, such as those from industry. Though volcanoes and their eruptions may seem like they should be big factors in the global CO2 budget, volcanoes release less than 1% of the CO2 emitted by human activities.

    Although the amount of CO2 emitted by Mauna Loa may be small in a global view, it could still yield important clues about Mauna Loa's volcanic processes and future eruptions. HVO hopes to find a location for the new gas monitoring station soon and have it installed in the coming months.

In the meantime, HVO does have a similar gas monitoring station high on Mauna Loa's Southwest Rift Zone, as well as another at Kīlauea summit. Even without our Mauna Loa summit station, we are still keeping an eye on our volcanoes and their degassing.

Both volcanoes in the park: Kīlauea caldera and its blackened lava lake,

and the sloping profile of Mauna Loa in the background under blue skies.

NPS Photo by J.Wei

Volcano Activity Updates

Kīlauea's eruption is paused. Its USGS Volcano Alert level is WATCH. The summit eruption at Kīlauea volcano—which has been confined to Halemaʻumaʻu crater—remains paused since June 19. Earthquake activity in the summit region has been low over the past week. Summit tiltmeters tracked gradual inflation and deflation for much of the past week. A sulfur dioxide (SO2) emission rate of approximately 160 tonnes per day was measured on Thursday, June 22.

Mauna Loa is not erupting. Its USGS Volcano Alert Level is at NORMAL.

    Webcams show no signs of activity on Mauna Loa. Seismicity remains low. Summit ground deformation rates indicate slow inflation as magma replenishes the reservoir system following the recent eruption. SO2 emission rates are at background levels.

    There were two earthquakes with 3 or more felt reports in the Hawaiian Islands during the past week: a M3.1 earthquake 17 km (10 mi) WSW of Kailua-Kona at 32 km (20 mi) depth on June 28 at 4:45 p.m. HST and a M3.1 earthquake 3 km (2 mi) SSW of Pāhala at 32 km (20 mi) depth on June 23 at 8:46 a.m. HST.

    HVO continues to closely monitor Kīlauea and Mauna Loa.

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THE DISCOVERY OF STARLIGHT FROM TWO MASSIVE GALAXIES GROWING BLACK HOLES was announced this week by an international team of scientists, including Chien-Hsiu Lee, staff astronomer at W. M. Keck Observatory on Maunakea. The quasars are from less than a billion years after the Big Bang. According to the Keck announcement: "The successful detection of these hosts represents the universe’s earliest epoch to date at which light from stars has been detected around a quasar."

    The Keck announcement says, "These black holes have masses close to a billion times that of the Sun, and the ratio of the black hole mass to host galaxy mass is similar to those seen in the more recent universe. Initially discovered in a deep survey program of the Subaru Telescope on Maunakea, the two quasars were then captured by the James Webb Space Telescope. This powerful combination of ground-based observations from Subaru Telescope and space-based observations from JWST has paved a new path to study the distant universe.

The zoomed-out image (left), the quasar image (center), and the host galaxy image after subtracting the quasar light (right) (from left to right). The image scale in light years is indicated in each panel.

Photo by Ding, Onoue, Silverman, et al., JWST NIRCam 3.6 μm image of HSC J2236+0032

    The study, led by Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) Project Researcher Xuheng Ding and Professor John Silverman, and Peking University Kavli Institute for Astronomy and Astrophysics (PKU-KIAA) Kavli Astrophysics Fellow Masafusa Onoue, is published in an online issue of the journal Nature this week.

    “This is the first time we’ve seen host galaxies from such an early age of the universe. It is only possible thanks to JWST’s deep images, which enable us to model and subtract the light from the quasar to reveal the host galaxy. We’ve seen quasars from this age previously, but they were so bright it was impossible to subtract their light to reveal the host galaxy,” said Lee, co-author of the study.

An infrared image of the Quasar HSCJ2236+0032 captured by JWST.

Photo by Ding, Onoue, Silverman, et al.

    Studying host galaxies and black holes in the early universe allows scientists to watch their formation and see how they are related to one another. Quasars are luminous while their host galaxies are faint, which has made it challenging for researchers to detect the dim light of the galaxy in the glare of the quasar, especially at great distances. Before the JWST, the Hubble Space Telescope was able to detect host galaxies of luminous quasars when the universe was just under 3 billion years old, but no younger.

    The superb sensitivity and ultra-sharp images of JWST at infrared wavelengths has finally allowed researchers to push these studies to the time when quasars and galaxies first formed. Just a few months after JWST started regular operations, the team observed two quasars, HSC J2236+0032 and HSC J2255+0251, at redshifts 6.40 and 6.34 when the universe was approximately 860 million years old, both of which were discovered using Subaru Telescope’s deep survey program. The relatively low luminosities of these quasars made them prime targets for measuring the properties of their host galaxies.

    The images of the two quasars were taken at infrared wavelengths of 3.56 and 1.50 microns with JWST’s NIRCam instrument, and the host galaxies became apparent after carefully modeling and subtracting glare from the accreting black holes. The stellar signature of the host galaxy was also seen in a spectrum taken by JWST’s NIRSPEC for J2236+0032, further supporting the detection of the host galaxy.

    Photometric analyses found that these two quasar host galaxies are massive, measuring 130 and 34 billion times the mass of the Sun, respectively. Measuring the speed of the turbulent gas in the vicinity of the quasars from the NIRSPEC spectra suggests the black holes that power them are also massive, measuring 1.4 and 0.2 billion times the mass of the Sun. The ratio of the black hole to host galaxy mass is similar to those of galaxies in the more recent past, suggesting that the relationship between black holes and their hosts was already in place 860 million years after the Big Bang.

“I’m excited to see powerful ground-based and space-based telescopes working together to tackle these challenges. Along with the Subaru Telescope, we will also be using Keck Observatory’s MOSFIRE instrument to identify similar targets that JWST can observe and enlarge the sample of ancient galaxies hosting quasars in the early universe,” said Lee.

    The team of astronomers will continue this study using scheduled Cycle 1 JWST observations, which will further inform models for the coevolution of black holes and their host galaxie.

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