Volcanic ash can create very fertile soil.
Jupiters Moons
Because there is no active volcanic activity on the moon. For a planet or moon to develop water, it needs to have active volcanic activity. The steam from erupting volcanoes creates an atmosphere and condensation which, over millions of years, creates oceans. We know the moon had active volcanic activity millions of years ago, because there are pockets of ice on the moon. However, volcanic activity on the moon is now non-existent, therefore, no more water can be produced from volcanic steam.
Tsunami
it is called a Lahar...
It is good for agriculture, as it is usually rich in nutrients and holds water well because of its volcanic ash content.
Lava gets cooled by water and becomes land... Other than that I can't think of anything else that's good about a volcanic eruptions
Volcanic ash can create very fertile soil.
Volcanic soil is good for growing plants because the soil that forms from volcanic rocks contain nutrients that many plants need to grow.
If there is liquid in volcanic rocks, it would most likely be water.
Not in the slightest.
Arsenal
to purify water
The most common volcanic gas released in an eruption is water vapor. Water vapor is followed by carbon dioxide and sulfur gas.
Good!
Yes, volcanic seamounts are the submarine mountains that haven't reacher the surface of the water. When they do, they become islands.
Jupiters Moons