Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Experimental Study on Tsunami Waves Induced by Submarine Landslides on Slope
Tianqing Lu, Haocheng Lu, Hua Liu*
MOE Key Laboratory of Hydrodynamics, School of NAOCE, Shanghai Jiao Tong University, Shanghai, China

However, more and more research has proven that using granularmaterial as landslides can get more satisfying results. In the past
decade, there were several great experiments on subaerial granular
landslide-generated tsunamis conducted by Heller and Hager (2010),
Viroulet et al (2014), McFall and Fritz (2016), and McFall et al (2018).
There are few studies on partially submerged landslides and submarine
landslides. Watts (1998) studied the waves generated by submarine
landslides using a solid triangular block. Grilli et al (2017) proposedthat the submarine landslide should generally be regarded as a flow
similar to a debris flow, and it is inaccurate to regard the landslide
body as a solid block. Fujii et al (2018) conducted landslide
experiments on deformable landslide bodies. Takabatake et al (2020)
conducted experiments on subaerial landslides, partially submergedlandslides, and submarine landslides, and they proposed the empiricalformulas for predicting the amplitudes of tsunami waves.

ABSTRACTAn experimental study of the submarine landslide on a slope and thetsunami waves is carried out in a wave flume. A slope with an
adjustable angle is designed to generate the landslide, and two sizes ofglass beads are used to study the influence of the percentages ofparticles with different sizes on the runout distance of the landslides.
The evolution of the interface between the granular landslide and thewater is obtained. It turns out that the runout distance of the landslides
composed of particles with different sizes tends to be smaller than thatof the landsides of uniform size particles due to the “repeated collisioneffect”. The changes of the wave amplitude and period of the leading
wave and the second wave along the wave flume are presented and thecorresponding empirical formulas are proposed.

In this paper, we carried out an experimental study on the submarine
landslide and the tsunami waves in a two- dimensional wave flume.
The process of collapsing and the influence of the percentages ofparticles with different sizes on the runout distance and the wave
periods of the leading wave and the second wave are presented.
Empirical formulas of predicting the amplitudes and periods of theleading wave and the second wave are developed.

KEY WORDS:

submarine landslide; landslide profile; runoutdistance; tsunami waves; wave period.

INTRODUCTION
Landslide tsunamis can be classified into three types: subaerial
landslides, partially submerged landslides, and submarine landslides,
according to the positional relationship between the place wherelandslides occur and the water surface. Submarine landslide tsunami
belongs to one of the most important types of tsunamis in tsunami
hazard assessment for coastal regions. In the South China Sea, thepotential impacts of the tsunamis induced by the Baiyun landslide ofdifferent scales on the coastal regions have been investigatednumerically. (Ren et al, 2019) Due to its nearshore disaster impact,
complex physical mechanism, difficulty to predict and early warning,
more attention should be paid to conduct well controlled laboratory
experiments to understand the mechanisms of the evolution of thesubmarine landslide and tsunami generation, particularly at thelandslides composed of different sizes of particles.

EXPERIMENTAL SET-UP
The experiments were conducted in a two-dimensional wave flume at
Shanghai Jiao Tong University as shown schematically in Fig.1. The
flume is 0.8m wide and 1.2m deep. The slope was made of an acrylic
board, while the remaining horizontal section has a smooth concrete
bottom. The lateral walls of the flume are made of glass, whichallowed the observation of the waves generated. A thin gate made ofengineering plastic was installed on the flume to generate a landslide.
The gate was connected to a weight with a nylon cord. Before starting
each test, the weight was lifted and the gate was closed. Glass beads,
which were used to model the landslide, were placed behind the gate.
When the gate was quickly lifted at a speed of 1.52m/s by releasing
weight, the glass beads slid into the water body and generated atsunami wave. 11 wave gauges were used to measure the time series of
the water surface elevations. All the gauges were placed along thecenterline of the flume to minimize the effects of the lateral wall. ToConducting experiments in a two-dimensional wave flume is a
traditional approach to study landslide tsunamis, among which thesubaerial landslide tsunamis are most extensively investigated. In thepast, solid sliders are often used to model landslide bodies. Kamphuisand Bowering (1972) conducted experiments with solid sliders.

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