Is the top of a volcano open or closed?

[kingwinner]

1) Is the top of a volcano open or closed? I mean, is there a hole in the top that connects to the mantle? If you still don't get what I am saying, lets put it this way, when you walk to the top of a volcano, is there a "land" that you can stand on the top or is it a hole?

From the following definition of a volcano, what I understand is that the top of a volcano is open, or there is a hole! But I am not sure! When the volcano is erupting, certainly there is a hole, but what if it isn't erupting yet? I have never seen a volcano from the top...

"...a volcano is a mountain that opens downward to a pool of molten rock below the surface of the earth. It is a hole in the Earth from which molten rock (magma) and gas erupt."

2) Are the terms "crater" and "caldera" meaning the same thing? (interchangeable?)

Would somebody like to share their knowledge?

[infamous]

Originally Posted by kingwinner

1) Is the top of a volcano open or closed?

When it's erupting, it would be open to the underlying magma. As the pressure is released and the magma cools, the caldera will form resulting in a rather flat and solid floor at the bottom of the crater.

Originally Posted by kingwinner

2) Are the terms "crater" and "caldera" meaning the same thing? (interchangeable?)

If I'm not mistaken the caldera is the floor of the crater so they represent two different things.

[kingwinner]

1) "a volcano is a mountain that opens downward to a pool of molten rock below the surface of the earth. It is a hole in the Earth from which molten rock (magma) and gas erupt"

Do you think the above definition is incorrect? (because a volcano doesn't always "open") I got it from http://www.woodlands-junior.kent.sch.../volcanoes.htm

3) Would explosive eruptions or quiet eruptions be more likely to increase the height of a volcano? I think exposive eruptions are more likely to increase the height because pyroclastic materials are ejected upward explosively. On the other hand, quiet eruptions allow lava to flow freely and quietly into wide areas. But how come cinder cone volcanoes, which only eject pyroclastic matierals, are not very tall? (sometimes even shield volcanoes are taller than them)

Thanks!