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Erosion controls direction of lava dome growing -- case study of the 2022-2024 island forming eruption at Home Reef (Tonga) analyzed from space

^^Simon Plank^1^, Emanuele Ciancia2,4, Nicola Genzano3, Alfredo Falconieri2,  Sandro Martinis1, Hannes Taubenböck1,5, Nicola Pergola2,4, Francesco Marchese2,4

  • Affiliations: 1German Aerospace Center DLR, German Remote Sensing Data Center, 82234, Oberpfaffenhofen, Germany; 2Institute of Methodologies for Environmental Analysis, National Research Council, 85050, Tito Scalo, Potenza, Italy; 3Department ABC (Architecture, Built Environment and Construction Engineering), Politecnico di Milano, Via Ponzio 31, 20133 Milano, Italy; 4Space Technologies and Application Center, University of Basilicata, 85100 Potenza, Italy; 5Earth Observation Research Cluster, University of Würzburg, 97074 Würzburg, Germany 

  • Presentation type: Poster

  • Presentation time: Thursday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 158

  • Lightning talk:

  • Programme No: 2.2.22

  • Theme 2 > Session 2

Abstract

The submarine volcano Home Reef is part of the Tonga Volcanic Arc, one of the most active volcanic arcs on Earth. On September 9, 2022 the Normalized Hotspot Indices (NHI) system, performing operationally at global scale, automatically notified the presence of a thermal anomaly at Home Reef Volcano from Sentinel-2 data. Starting from this information, we integrated multi-sensor/multi-platform satellite datasets, including very high spatial resolution multispectral data of PlanetScope and radar data of TerraSAR-X, as well as infrared data from Sentinel-2, Landsat-8/9, MODIS and VIIRS, to monitor and characterize the youngest eruption at the Home Reef Volcano over a two-years period. Based on this multi-sensor approach, we investigated the eruption dynamics (e.g., in terms of thermal activity and relative intensity level) and studied the lava dome growing and erosion processes. The island forming eruption showed four distinct phases: First, lava dome growing formed an approx. 54,900 m² large circular shaped island during September to October 2022. In the following, further dome growing phases towards the south (September--November 2023) and east (January 2024 and June--September 2024) extended the island to over 122,000 m². We show that erosion processes control the location of the new vent, which is then active in the next phase, and therefore predetermine the growing direction of the next phase lava dome. The latter might be crucial for the location of a potential tsunami-genic landslide-like dome collapse.