Calving induced tsunamis in the Wolstenholme Fjord (Greenland)

Tsunamis are rare but potentially highly destructive natural phenomena, posing a serious threat to coastal environments and communities in many parts of the world. Historical catalogues tell that about 70% of the tsunamis worldwide are generated by submarine or coastal earthquakes, while the remaining 30% includes landslides, volcanic eruptions, atmospheric disturbances, and calving. Especially in light of the rapidly changing global climate conditions, calving is gaining increasing attention in the tsunami research community. This study aims at describing calving generation mechanism, focusing on observations and modelling. Unlike earthquake-generated tsunamis, the mechanisms behind iceberg calving and the resulting water displacement are poorly understood and more difficult to model. The dynamics and unpredictable nature of calving events make it essential to improve our understanding of how these tsunamis form and propagate. Data from the Italian MACMAP Project (A Multidisciplinary Analysis of Climate Change Indicators in the Mediterranean and Polar Regions) coordinated by the Istituto Nazionale di Geofisica e Vulcanologia (Italy) is used to achieve this goal. In fact, the project operates a meteo-hydrometric station at Wolstenholme Fjord, Greenland, which provides continuous measurements of crucial parameters such as instantaneous, minimum, and maximum sea level measures, which are useful for studying calving-induced tsunamis in the basin. To model the tsunami initial conditions, generated by the calving events, a paraboloid shape is employed, with crests surrounding the block of ice falling into water. This geometry has been chosen due to its ability to replicate the initial displacement patterns observed in calving dynamics as described in Hu (2022) and in Huang (2023). The simulations are carried out by means of the JAGURS software for different geometries of the ice body and in different locations based on potential sources observed in the study fjord. The available tide gauge time histories are used to validate the results of the numerical modeling, aiming at acquiring knowledge of the calving source and quantifying the detached ice mass.