Multilayer modelling of waves generated by explosive submarine volcanism

Abstract

Abstract. Theoretical source models of underwater explosions are often applied in studying tsunami hazards associated with submarine volcanism; however, their use in numerical codes based on the shallow water equations can neglect the significant dispersion of the generated wavefield. A non-hydrostatic multilayer method is validated against a laboratory-scale experiment of wave generation from instantaneous disturbances and at field-scale submarine explosions at Mono Lake, California, utilising the relevant theoretical models. The numerical method accurately reproduces the range of observed wave characteristics for positive disturbances and suggests a previously unreported relationship of extended initial troughs for negative disturbances at low dispersivity and high nonlinearity parameters. Satisfactory amplitudes and phase velocities within the initial wave group are found using underwater explosion models at Mono Lake. The scheme is then applied to modelling tsunamis generated by volcanic explosions at Lake Taupō, New Zealand, for a magnitude range representing ejecta volumes between 0.04–0.4 km3. Waves reach all shores within 15 minutes with maximum incident crest amplitudes around 4 m at shores near the source. This work shows that the multilayer scheme used is computationally efficient and able to capture a wide range of wave characteristics, including dispersive effects, which is necessary when investigating submarine explosions. This research therefore provides the foundation for future studies involving a rigorous probabilistic hazard assessment to quantify the risks and relative significance of this tsunami source mechanism.

Numerical Simulation of Tsunami Impact From the 1/15/22 Eruption of the Hunga Tonga - Hunga Ha’apai Volcano

“…communication) and around HTHHV. We modeled explosion tsunami sources ranging from 3 to 10 Mt, with an initial surface elevation defined using a semi-empirical method, similar to Hayward et al (2022) (Fig. 1c).…”

Probabilistic Landslide Tsunami Estimation in the Makassar Strait, Indonesia, Using Statistical Emulation

“…The numerical scheme implemented is described in further detail by Popinet (2020), and has been validated for wave propagation and runup (Hayward, Whittaker, Lane, & Power, 2022; Hayward, Whittaker, Lane, Power, Popinet, & White, 2022) and against various benchmarks, from simplified evolution of tsunami‐like perturbations and periodic wave propagation to real cases such as the modeling of the dispersive features of the 2011 Tohoku earthquake tsunami (Popinet, 2020).…”