The evolution of the 2022-2024 eruption at Home Reef, Tonga, analyzed from space shows vent migration due to erosion.

On September 9, 2022, a new eruption period began at the submarine volcano Home Reef, part of the Tonga Volcanic Arc. We integrated multi-sensor/multi-platform satellite datasets, including very high spatial resolution TerraSAR-X radar and PlanetScope multispectral data, together with Sentinel-2 and Landsat-8/9 as well as MODIS and VIIRS thermal data to monitor and characterize this latest eruption at Home Reef over a two-year period. Here, we present the results from this multi-sensor approach, used to investigate eruption dynamics (thermal activity and relative intensity level) and delineate changes in the shape and area of the newly formed island. The eruption showed four distinct phases: During September-October 2022, lava flows formed a ~ 54,900 m² circular island. In the following three eruption phases, the island grew towards the south (September-November 2023) and east (January 2024 and June-September 2024), expanding the island's area to over 122,000 m². During each subsequent phase, the eruptive vent migrated toward the side of the island where the most erosion had occurred since the previous phase. This has implications for volcanic and tsunami hazards from island-forming eruptions of this type.