Simultaneous creation of a large vapor plume and pumice raft by a shallow submarine eruption

et al. 2022

Commun Earth Environ

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The 15 January 2022 eruption of Hunga Tonga-Hunga Ha’apai, and the preceding eruptions on 19 December 2021 and 13 January 2022, were remarkable, partly because the eruptions generated extensive umbrella clouds, regions where the volcanic clouds spread laterally. Here we use satellite remote sensing to evaluate the umbrella cloud tops’ heights, longevities, water contents, and volumetric flow rates. We identified two umbrella clouds at distinct elevations on 15 January 2022. Specifically, after 05:30 UTC, the strong westward propagation of an upper umbrella cloud at 31 km ± 3 km enabled the visibility of the lower umbrella cloud at 17 km ± 2 km. The satellite-derived volumetric flow rate for 15 January 2022 was ~5.0 × 1011 m3 s−1, nearly two orders of magnitude higher than the volumetric flow rates estimated for the 19 December 2021 and 13 January 2022 eruptions. Finally, we found that the umbrellas on all three dates were ice-rich.

Section: Discussionmentioning

confidence: 99%

Eruption chronology of the December 2021 to January 2022 Hunga Tonga-Hunga Ha’apai eruption sequence

Gupta

Bennartz

et al. 2022

Commun Earth Environ

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“…and marine organisms across thousands of kilometers, potentially dispersing nutrients and increasing microbial biomass and biodiversity in areas geographically distant from the site of the eruption (DeVantier, 1992;Risso et al, 2002;Bryan et al, 2012). Pumice rafts can also be a significant hazard for human maritime activities, especially by clogging harbors and affecting near shore sea life and fisheries, disrupting local economies (Bryan et al, 2012;Jutzeler et al, 2020), as observed in the recent raft dispersal from the 2021 eruption of Fukutoku-Okanoba volcano, a submarine volcano in the Bonin Arc (24.285 °N, 141.481 °E) (Fauria et al, 2022;Yoshida et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

Pumice Raft Detection Using Machine-Learning on Multispectral Satellite Imagery

Zheng

Mittal

et al. 2021

Preprint

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Most of Earth's volcanic eruptions occur underwater, and these submarine eruptions can significantly impact large-scale Earth systems (e.g., enhancing local primary production by phytoplankton). However, detecting submarine eruptions is challenging due to their remote locations, short eruption durations, lack of sea surface signature (if eruptions do not breach the surface), and the transient nature of the surface manifestations of an eruption (e.g., floating pumice clasts, hydrothermal fluids). We can utilize global satellite imagery of 10-30 m resolution (e.g., Landsat 8, Sentinel-2) to detect new eruptions; however, the large data volumes make it challenging to systematically analyze satellite imagery globally. In this study, we address these challenges by developing a new semiautomated analysis framework to detect submarine eruptions through supervised classification of satellite images on Google Earth Engine. We train our algorithm using images from rafts produced by the August 2019 eruption of Volcano F in the Tofua Arc and present a case study using our methodology on satellite imagery from the Rabaul caldera region in Papua New Guinea. We potentially find a large number of new unreported pumice rafts (in ~16% of images from 2017-present). After analysis of the spatial pattern of raft sightings and ancillary geophysical and visual observations, we interpret that these rafts are not the result of a new eruption. Instead, we posit that the observed rafts represent remobilization of pumice clasts from previous historical eruptions. This novel process of raft remobilization may be common at near-shore/partially submarine caldera systems (e.g., Rabaul, Krakatau) and may have significant implications for new submarine eruption detection and volcanic stratigraphy.

Timelines of plume characteristics of the Hunga Tonga-Hunga Ha'apai eruption sequence from 19 December 2021 to 16 January 2022: Himawari-8 observations

Gupta

Bennartz

et al. 2022

Preprint

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