Large-scale experiments into the tsunamigenic potential of different iceberg calving mechanisms

• Published in: Scientific Reports
• Main Authors: Heller, Valentin (author), Chen, Fan (author), Brühl, Markus (author), Gabl, Roman (author), Chen, X. (author), Wolters, Guido (author), Fuchs, Helge (author)
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2019
• Subjects: greenlandic; Ice Sheet
• Online Access: http://resolver.tudelft.nl/uuid:5ba8c128-10a4-4791-917f-6b75a8865f53; https://doi.org/10.1038/s41598-018-36634-3

Mass balance analysis of ice sheets is a key component to understand the effects of global warming. A significant component of ice sheet and shelf mass balance is iceberg calving, which can generate large tsunamis endangering human beings and coastal infrastructure. Such iceberg-tsunamis have reached amplitudes of 50 m and destroyed harbours. Calving icebergs interact with the surrounding water through different mechanisms and we investigate five; A: capsizing, B: gravity-dominated fall, C: buoyancy-dominated fall, D: gravity-dominated overturning and E: buoyancy-dominated overturning. Gravity-dominated icebergs essentially fall into the water body whereas buoyancy-dominated icebergs rise to the water surface. We find with unique large-scale laboratory experiments that iceberg-tsunami heights from gravity-dominated mechanisms (B and D) are roughly an order of magnitude larger than from A, C and E. A theoretical model for released iceberg energy supports this finding and the measured wave periods upscaled to Greenlandic outlet glaciers agree with field observations. Whilst existing empirical equations for landslide-tsunamis establish estimates of an upper envelope of the maximum iceberg-tsunami heights, they fail to capture the physics of most iceberg-tsunami mechanisms. Hydraulic Structures and Flood Risk