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Abstract

The Hunga Tonga Hunga Ha’apai (HTHH) islands have evolved since 2014, as we trace back through the SAR and multispectral satellite imaging of the Sentinels 1 and 2. The modulations of the outline of the islands are accompanied by mass changes, possibly detectable through a variation of the gravity field. These mass changes are the sum of the height changes of the emerging parts of the volcano, and the volume changes concealed below the ocean surface. The goal of the study is to define realistic mass changes that are associated to the evolution of HTHH, then to estimate the gravity changes in space and time, and finally estimate the sensitivity of observational methods to the gravity changes. Present ongoing efforts define the noise level in acquisitions of multi-satellite constellations carrying innovative instrumentation as quantum technology gravimeters or gradiometers [1,2]. The MAGIC mission planned for end of the 2020ties shall combine an inclined and polar pair of a GRACE-like mission to achieve a significant improvement in the recovery of the time variable gravity field. We find that the improvements of the future satellite missions should allow us to detect the subsurface mass changes generated by submarine volcanic activity, although the estimated mass changes for HTHH pose a challenge for the detectability. Next to HTHH we make a review of other known submarine eruptions and find that bigger volcanic mass changes are documented, which could be effectively observed. References[1] Migliaccio et al. (2023). SurvGeophys, https://doi.org/10.1007/s10712-022-09760-x[2] Pivetta et al. (2022). RemoteSensing, https://doi.org/10.3390/rs14174278