Taro Kakinuma Taro Kakinuma

34 Tsunami

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http://dx.doi.org/10.5772/64530

## **Abstract**

Tsunamis can be triggered by not only submarine earthquakes, but also by landslides, and submarine volcanic eruptions. First, several characteristics of tsunami generation due to a landslide, or a sector collapse, are studied, with the tsunamis simulated numerically, to represent their generation through an interaction between falling bodies, and seawater, in two vertical dimensions. The falling body is assumed to be a fluid, or a rigid body, which moves down a slope with a constant gradient. Second, the mechanism of tsunami generation caused by a submarine volcanic eruption, is discussed, focusing on a phreatomagmatic explosion, where after exposure to high temperature magma, seawater evaporates instantly, with an explosive increase in its volume. An index for submarine volcanic explosive force, concerning tsunami generation, has been developed, by assuming the relationship between a phreatomag‐ matic explosion, and the resultant initial tsunami waveform. A numerical simulation was also generated, with a specific value for this index, for the propagation of tsunamis due to a submarine volcanic eruption in Kagoshima Bay, where a submarine explosion, leading to tsunami generation, has been observed.

**Keywords:** tsunami, landslide, sector collapse, submarine volcanic eruption, phreato‐ magmatic explosion
