Re: If all the volcanoes erupted at the same time would it be possible to empty

Dear Linda,

The quick answer to your question is, no, I doubt it. The reason why the molten core of the earth would not empty out if all the volcanoes erupted at once is as follows.

First of all, let's take a look at a map of the world that shows all the locations of active volcanoes. A good map that allows you to see volcanoes from all over the world is at http://volcano.und.nodak.edu/vwdocs/volc_images/volc_images.html. You will notice that for the most part, all current active volcanoes are located near the margins of the continents and in the middle of the oceans. The reason for this is because volcanoes form along two areas on the earth's surface, at subduction zones or along midoceanic ridges where new crust is being formed. An exception to this are volcanoes that are located at 'hot spots' in the Earth's crust, like Hawaii.

As you may know, the surface of the earth is covered in several tectonic plates that are actually in motion. Where one tectonic plate is being driven under another plate, a subduction zone is created. A good example of this is along the western coast of the US. Along the west coast, the Pacific Plate is being driven under the North American Plate. As the Pacific Plate is pushed under, the material that made up that plate is being subjected to intense heat and pressures, which causes the plate to melt and the material begins to rise up under the North American Plate. Where the hot magma reaches the surface, a volcano can form. A good example is Mt. St. Helens in Washington State. Subduction zones are also areas of intense earthquake activity. Incidentally, these subduction zones are where the deepest trenches on earth are, like the Marianas Trench in the Pacific.

Midoceanic ridges, as the name implies, are in the ocean. The difference here is that this is an area where new crust for the earth is being made. Magma from the interior of the earth (not the center of the earth) wells up a long a ridge and then spreads out to the side. As it does so, it pushes older crust out away from the ridge, therefore making the plate spread. The Mid-Atlantic Ridge is a good example of this, and Iceland is a good example of volcanism that takes place along a midoceanic ridge.

Another item to note is that when a volcano erupts, it serves to reduce the pressure build up that is present in that part of the earth's crust, much the same way that an exhaust valve on a steam pressure cooker will open up if the steam pressure gets too high. So, therefore, it would be highly unlikely to see all the volcanoes erupt at once because a few eruptions could reduce the pressure build up of other volcanoes.

Getting back to your question, if all the volcanoes were to erupt at once, the core of the earth would not be emptied. Volcanoes do not have 'roots' that extend all the way to the core of the earth, rather the magma that comes up has its source relatively shallow in the earth. That is not to say that if all the volcanoes went off at once it would not be a major planetary disaster! For an interesting web site about volcanoes, try http://volcano.und.nodak.edu/vw.html.

I hope this helps you.
Best regards,
Ted