Iceberg A-76a Late-Stage Monitoring with a Seismometer and Satellite Remote Sensing Evidence

Giant Antarctic tabular icebergs travel northward until they disintegrate and melt.Tracking their movement and state is challenging because remote sensing is sporadic. Combining a close-by seismic station and evidence from the SWOT KaRIn SSHA and MODIS True Color imagery, we achieved daily reconstruction of the A-76a iceberg's late-stage evolution (March-July 2023). Seismic spectrograms revealed bursts, harmonic tremors, and a micro-tsunami signal, with locations validated by satellite images. Bursts were associated with iceberg fracturing, tremors with seafloor scraping and collisions, and a micro-tsunami with capsizing. This study demonstrates the value of integrating remote sensing and seismic data to monitor iceberg dynamics. It is the first to observe a micro-tsunami with SWOT that generates a seiche-like signal on the 37-km-distant II.HOPE station. This approach astutely combines the strengths of continuous seismic monitoring and large-area satellite imaging to monitor this massive tabular iceberg.