Spatial Impulse Wave Generation and Propagation

Abstract

Rapid landslides into water bodies may generate massive water waves posing a threat to riparian settlements and infrastructure. These waves are referred to as impulse waves and exhibit tsunami-like characteristics. The generation and in particular the spatial propagation of impulse waves was studied in a hydraulic laboratory wave basin. A videometric measurement system was applied to track the water surface displacement. Compared to fixed wave gauges typically applied in previous studies, this technique yields a quasi-continuous representation of the water surface allowing for a detailed analysis of spatial propagation patterns. In total 74 experiments with deformable mesh-packed slides were conducted thereby varying the slide impact velocity, the slide mass, the slide thickness, the slide width, the slide impact angle, and the stillwater depth. Empirically derived prediction equations are presented and discussed for key wave characteristics including wave amplitudes and celerities. In the context of a preliminary hazard assessment, these equations allow for the estimation of wave magnitudes at prototype-scale.

Impulse Wave Runup on Steep to Vertical Slopes

“…the measured impulse wave celerities mainly scatter between 95% and 103% of the solitary wave celerity. This agrees with the findings by McFall and Fritz [23] and Evers et al [24] for spatial impulse wave propagation in wave basins. The relative wave length L/h of Müller's [7] experiments range between 9 and 56.…”

A Simplified Classification of the Relative Tsunami Potential in Swiss Perialpine Lakes Caused by Subaqueous and Subaerial Mass-Movements

“…Considering only the parameters imposed by the topography, large drop heights and steep slope angles induce high slide velocities. Based on experiments in a wave basin, Evers et al (2019a) found the slide width to be an additional governing parameter for 3D wave generation and propagation: The wider a slide, the larger the wave.…”

Run-Up of Impulse Wave Trains on Steep to Vertical Slopes

“…While a first wave is generated due to the direct impact of the slide, it may be followed by several further waves due to the drawdown and run-up along the shore after the initial impact. Such series of multiple wave crests and troughs are referred to as impulse wave trains (Mohammed and Fritz 2012;McFall and Fritz 2016;Evers et al 2019a). As the initial wave heights can be significantly larger than those of earthquake-induced tsunamis, such waves are also known as megatsunamis.…”

“…McFall and Fritz (2016) came to similar results, with the second wave being on average 23% slower than the first wave. Evers et al (2019a) compared the measured first and second wave crest celerity with the solitary wave celerity cSol and found that on average c1 = 0.95cSol and c2 = 0.7cSol, respectively. This matches well with the present findings, for which the wave crest celerity of wave i within the wave train may be predicted by ,…”

“…For general water bodies like reservoirs, both wave generation and propagation are three-dimensional (3D). The slide impact energy is transferred to a wider water column and the slide width b has a major effect on the wave generation (Evers et al 2019a). The subsequent wave propagation is omnidirectional and besides the propagation distance, the wave characteristics also depend on the wave propagation angle (Huber and Hager 1997).…”