More Like this

1. The Impact of 2022 Hunga Tonga‐Hunga Ha'apai (Hunga) Eruption on Stratospheric Circulation and Climate

   https://doi.org/10.1029/2024JD042943  

   Yook, Simchan; Solomon, Susan; Wang, Xinyue (March 2025, Journal of Geophysical Research: Atmospheres)

   Abstract The Hunga Tonga‐Hunga Ha'apai (Hunga) volcanic eruption in January 2022 injected a substantial amount of water vapor and a moderate amount of SO₂into the stratosphere. Both satellite observations in 2022 and subsequent chemistry‐climate model simulations forced by realistic Hunga perturbations reveal large‐scale cooling in the Southern Hemisphere (SH) tropical to subtropical stratosphere following the Hunga eruption. This study analyzes the drivers of this cooling, including the distinctive role of anomalies in water vapor, ozone, and sulfate aerosol concentration on the simulated climate response to the Hunga volcanic forcing, based on climate simulations with prescribed chemistry/aerosol. Simulated circulation and temperature anomalies based on specified‐chemistry simulations show good agreement with previous coupled‐chemistry simulations and indicate that each forcing of ozone, water vapor, and sulfate aerosol from the Hunga volcanic eruption contributed to the circulation and temperature anomalies in the SH stratosphere. Our results also suggest that (a) the large‐scale stratospheric cooling during the austral winter was mainly induced by changes in dynamical processes, not by radiative processes, and that (b) the radiative feedback from negative ozone anomalies contributed to the prolonged cold temperature anomalies in the lower stratosphere (∼70 hPa level) and hence to long lasting cold conditions of the polar vortex. 

   more » « less
2. NUMERICAL SIMULATION OF TSUNAMI IMPACT FROM THE 1/15/22 ERUPTION OF THE HUNGA TONGA - HUNGA HA’APAI VOLCANO

   https://doi.org/10.9753/icce.v37.management.85  

   Grilli, Stephan; Mohammadpour, Maryam; Grilli, Annette; Zhang, Cheng; Tappin, Dave; Novellino, Alessandro; Watt, Sebastien (September 2023, Coastal Engineering Proceedings)

   Tsunamis from volcanic ‘explosive’ eruptions are rare, with the last catastrophic event being Krakatau in 1883 (Verbeek, 1885), during which, tsunamis were generated in the far-field by pressure shock-waves and in the nearfield of the volcano, in the Sunda Straits, by several potential geological mechanisms including pyroclastic flows, ash column, and/or caldera collapse. On 1/22/55, at about 4:15 UTC, a one in 1,000 year eruption of the Hunga Tonga-Hunga Ha’a-pai Volcano (HTHHV), that had started on12/20/21, reached its paroxysm with a series of large underwater explosions, releasing enormous energy (4-18 Mt of TNT), and ejecting a large ash plume 58 km into the stratosphere. We simulate both the near- and far-field tsunami generation from the eruption, but in this paper we focus on analyzing and validating the near-field impact against field data. 

   more » « less
3. Stratospheric Chlorine Processing After the Unprecedented Hunga Tonga Eruption

   https://doi.org/10.1029/2024GL108649  

   Zhang, Jun; Wang, Peidong; Kinnison, Douglas; Solomon, Susan; Guan, Jian; Stone, Kane; Zhu, Yunqian (September 2024, Geophysical research letters)

   Abstract Following the Hunga Tonga–Hunga Ha'apai (HTHH) eruption in January 2022, significant reductions in stratospheric hydrochloric acid (HCl) were observed in the Southern Hemisphere mid‐latitudes during the latter half of 2022, suggesting potential chlorine activation. The objective of this study is to comprehensively understand the loss of HCl in the aftermath of HTHH. Satellite measurements and a global chemistry‐climate model are employed for the analysis. We find strong agreement of 2022 anomalies between the modeled and the measured data. The observed tracer‐tracer relations between nitrous oxide (N₂O) and HCl indicate a significant role of chemical processing in the observed HCl reduction, especially during the austral winter of 2022. Further examining the roles of chlorine gas‐phase and heterogeneous chemistry, we find that heterogeneous chemistry emerges as the primary driver for the chemical loss of HCl, and the reaction between hypobromous acid (HOBr) and HCl on sulfate aerosols is the dominant loss process. 

   more » « less
4. How Did Westward Volcaniclastic Deposits Accumulate in the Deep Sea Following the January 2022 Eruption of Hunga Volcano?

   https://doi.org/10.1029/2024GC011629  

   Chaknova, Marcus; Giachetti, Thomas; Paredes‐Mariño, Joali; Soule, Adam; Van_Eaton, Alexa R; Beinart, Roxanne; Crundwell, Martin; Cronin, Shane J; Jutzeler, Martin; Fauria, Kristen E; et al (April 2025, Geochemistry, Geophysics, Geosystems)

   Abstract Most volcanic eruptions on Earth take place below the ocean surface and remain largely unobserved. Reconstruction of past submerged eruptions has thus primarily been based on the study of seafloor deposits. Rarely before the 15 January 2022 eruption of Hunga volcano (Kingdom of Tonga) have we been able to categorically link deep‐sea deposits to a specific volcanic source. This eruption was the largest in the modern satellite era, producing a 58‐km‐tall plume, a 20‐m high tsunami, and a pressure wave that propagated around the world. The eruption induced the fastest submarine density currents ever measured, which destroyed submarine telecommunication cables and traveled at least 85 km to the west to the neighboring Lau Basin. Here we report findings from a series of remotely operated vehicle dives conducted 4 months after the eruption along the Eastern Lau Spreading Center‐Valu Fa Ridge. Hunga‐sourced volcaniclastic deposits 7–150 cm in thickness were found at nine sites, and collected. Study of the internal structure, grain size, componentry, glass chemistry, and microfossil assemblages of the cores show that these deposits are the distal portions of at least two ∼100‐km‐runout submarine density currents. We identify distinct physical characteristics of entrained microfossils that demonstrate the dynamics and pathways of the density currents. Microfossil evidence suggests that even the distal parts of the currents were erosive, remobilizing microfossil‐concentrated sediments across the Lau Basin. Remobilization by volcaniclastic submarine density currents may thus play a greater role in carbon transport into deep sea basins than previously thought. 

   more » « less
5. Airfall volume of the 15 January 2022 eruption of Hunga volcano estimated from ocean color changes

   https://doi.org/10.1007/s00445-024-01744-6  

   Kelly, Liam_J; Fauria, Kristen_E; Manga, Michael; Cronin, Shane_J; Latu’ila, Folauhola_Helina; Paredes-Mariño, Joali; Mittal, Tushar; Bennartz, Ralf (May 2024, Bulletin of Volcanology)

   Abstract On 15 January 2022, Hunga volcano erupted, creating an extensive and high-reaching umbrella cloud over the open ocean, hindering traditional isopach mapping and fallout volume estimation. In MODIS satellite imagery, ocean surface water was discolored around Hunga following the eruption, which we attribute to ash fallout from the umbrella cloud. By relating intensity of ocean discoloration to fall deposit thicknesses in the Kingdom of Tonga, we develop a methodology for estimating airfall volume over the open ocean. Ash thickness measurements from 41 locations are used to fit a linear relationship between ash thickness and ocean reflectance. This produces a minimum airfall volume estimate of$${1.8}_{-0.4}^{+0.3}$$ ${1.8}_{-0.4}^{+0.3}$km³. The whole eruption produced > 6.3 km³of uncompacted pyroclastic material on the seafloor and a caldera volume change of 6 km³DRE. Our fall estimates are consistent with the interpretation that most of the seafloor deposits were emplaced by gravity currents rather than fall deposits. Our proposed method does not account for the largest grain sizes, so is thus a minimum estimate. However, this new ocean-discoloration method provides an airfall volume estimate consistent with other independent measures of the plume and is thus effective for rapidly estimating fallout volumes in future volcanic eruptions over oceans. 

   more » « less