Large-scale investigation into iceberg-tsunamis generated by various iceberg calving mechanisms

Valentin Heller, Tommaso Attili, Fan Chen, Roman Gabl, Guido Wolters

Research output: Contribution to journalArticlepeer-review

Abstract

Mass balance analysis of ice sheets is a key component to understand the effects of global warming with iceberg calving as a significant contributor. Calving recently generated tsunamis of up to 50 m in amplitude endangering human beings and coastal infrastructure. Such iceberg-tsunamis (IBTs) have been investigated based on 66 unique large-scale experiments conducted in a 50 m × 50 m large basin at constant water depth h. The experiments involved five iceberg calving mechanisms: A: capsizing, B: gravity-dominated fall, C: buoyancy-dominated fall, D: gravity-dominated overturning and E: buoyancy-dominated overturning. The kinematics of the up to 187 kg heavy plastic blocks mimicking icebergs was measured with a motion sensor and the wave profiles were recorded with wave probes at up to 35 locations. The IBTs from the gravity-dominated mechanisms (B and D) are roughly an order of magnitude larger than from mechanisms A, C and E. Empirical equations for preliminary hazard assessment and mitigation for the maximum wave height, amplitude and period for both the near- and far-field are derived for the five calving mechanisms individually and combined. The relative released energy, Froude number and relative iceberg width are the most influential dimensionless parameters in these equations. A maximum wave height decay trend close to (r/h)−1.0 is observed, with r as the radial distance, in agreement with the theoretical wave decay from a point source. The empirical equations are applied to a past event resulting in a good agreement and the upscaled wave periods to typical Greenlandic conditions overlap with the lower spectrum of landslide-tsunamis. However, empirical equations for landslide-tsunamis were found to be of limited use to predict IBTs in the far-field supporting the need of the newly introduced empirical equations for IBT hazard assessment and mitigation.
Original languageEnglish
Article number103745
JournalCoastal Engineering
Volume163
Early online date25 Jun 2020
DOIs
Publication statusPublished - Jan 2021

Keywords / Materials (for Non-textual outputs)

  • Greenland
  • Iceberg calving
  • Iceberg-tsunami
  • Impulse wave
  • Landslide-tsunami
  • Outlet glacier
  • Physical modelling

Fingerprint

Dive into the research topics of 'Large-scale investigation into iceberg-tsunamis generated by various iceberg calving mechanisms'. Together they form a unique fingerprint.

Cite this