Volcanoes

If there is an Earth quake under the bed of the ocean and as a result the bottom is lifted upwards, then all of a sudden there is a whole heap of water being pushed upwards as well. If this happen on land the land would become higher and stay there, however when it happens to water it forms a wave as the surface of the ocean levels out again, this wave can have an enormous amount of water and force behind it depending on how much the seabed has lifted and can be bad news for any one on shore in its path.

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During a volcanic eruption, lava, tephra (ash, lapilli, volcanic bombs and blocks), and various gases are expelled from a volcanic vent or fissure.

Convergent plate volcanism

Height of the main vent of the volcano

A mixture of gases