Why does spreading of lava and ridge formation occur on the sea floor most commonly?

Answer 1

Because only at Divergent Plate Boundaries, ocean ridges are formed. Most known is the Mid-Atlantic Ridge. Also, most of the Earth's volcanoes are in the ocean floor.

When two plates separate, it's going to cause the hot mantle to rise (thermal uplift) forming new oceans such as the Red Sea, or ridges such as Mid-Atlantic Ridge.

Answer 2

I think you are asking why most spreading ridges (divergent plate boundaries) are below sea level.
Here's why...
The earth has a lot of water, as you know. And that water piles up in all the lowest places on the earth's surface.
The brand new crust created at a spreading ridge is very thin and is relatively dense. For this reason, the volcanism at the spreading ridges usually doesn't make high areas that rise above sea level. Iceland is an exception. In other words, ocean crust is thin and dense, and forms low areas---and water accumulates in low areas.

In contrast, the crust of continents is very thick and less dense than ocean crust, so the continents sort of float on the mantle like big ice cubes in a glass of water. Convergent plate boundaries often create this kind of thicker, less dense crust. So, islands like Japan get built, or rising coastlines like Seattle's get built.

Answer 3

It is probably due to two factors. First, the ocean basin's occupy 70% of the Earth's surface, so they are more likely to be there. Secondly, even when rifting does occur on the continent, it eventually becomes an ocean basin. When North America and South America rifted from Eurasia and Africa it created the Atlantic Ocean with its mid-oceanic ridge. As Arabia is seperating from Africa it has created the Red Sea, which someday will become an ocean with a mid-oceanic ridge.

Answer 4

There is a recent discovery that claims that the earh's tectonic plates spread out on one side of the earth and get smashed together on the opposite side of the earth. The tectonic plates get recycled when they finally buckle and get thrust back toward the earth's core on th ridge side. While the spreading lava is creating new crust on the opposite side of the Earth. I don't remember the locations of the sides, but I know either the Atlantic or Pacific Ocean is getting larger and vice versa.

Answer 5

definite mid-ocean ridges an sea-floor spreading are linked. the mid-ocean ridge is a community it is mountainess and the spreading is slower interior the Atlantic.yet interior the Pacific the mid- ocean ridge is plenty mushy it greater like hills. the spading of the sea ridges are brought about via the plate limitations shifting aside form one yet another in diverse instructions

Answer 6

Because diverging plates will end up in the lowest spot as compared to converging boundaries. For example, if the East Africa rift zone continues to diverge, then it is likely that it will become submerged. Rift zones don't favor sea floors, they help to cause them. A sea floor is a consequence of diverging plates.

Answer 7

because most of the earth's plate boundies are under water .