Taking out, moving and building bad for our planet?

[Shinx3000]

I was bored a while ago and randomly thought about this...

We take things out of the earth. Blasing rocks, digging holes and removing oil from under the ground and more. We take all this out, would it not weaken under the earth or make the earth less the weight that it used to be and or make the underground more unstable?

I thought about something else to, the stuff we mine from the earth goes into building matatiels and things and we build massive skyscrapers and buildings etc... Would that not offset the balance of the earth? Taking huge amounts out of one side of the earth and creating big buildings and other things on another part of the earth? That would put more pressure on one side of the earth and less on the part that was mined out I think.

I know this won't really apply, dcause it won't get like this here, but in a futurama episode, a planet imploded on itself because it was mined hollow.

 

[Rayne]

I don't think you have to worry about any sort of 'implosions' or cave ins anytime soon.

First of all, the earth has naturally been creating imbalances all the time. Take the Himalayas for instance. At one point in time, that area of earth was probably no flatter than sea level, but due to tectonic movement, suddenly we have miles high mountains and the earth hasn't collapsed yet. For comparison, Mt. Everest is about 5.5 miles (8.85km) high and increasing. The soon to be largest building, and now largest man made structure in the world, the Burj Dubai is estimated to be a mere half-mile high (.818km). This doesn't even account for the volume of the mountain and to account for all the densities, I'm sure you would get something surpassing the weight of Manhattan.

Most man made tunnels and such are excavated away from cities, usually in mountainous areas. I mean, head clearance of some of these tunnels barely leave enough room to stand. Transportation network tunnels are probably the only tunnels I can think of that are large, but those are engineered in such a way to prevent collapse. (And historically, places like Manhattan, and a ton of other world cities like London, France and Rome have vast, old underground tunnel networks that haven't caved in and shows you how reliable human engineering and the natural bedrock are in those structures.) We make pretty wimpy tunnels compared to the already extensive natural underground chasms that exist.

Natural caves already exist underneath the surface, they happen to have just the proper rigid structure to prevent a cave in. This isn't to say cave ins don't happen. This is totally possible without human interaction, be it through tectonic movement or erosion of the underlying structures that eventually cause them to collapse.

In terms of human intervention, our holes are hardly a dent in the overall make up of the earth's crust. The most common materials that make things like concrete and bricks are mined at the surface in quarries. And for material such as crude oil, this stuff is under intense pressure anyway and the settling of rocks will just expand or further compact to fill in these voids or as in the instances described above, the rocks are capable of supporting their own weight even when new voids are created. And moving this material around to other places isn't adding any mass to the earth, it was always apart of the earth's mass.

So does this make cities invulnerable? Not by a long shot. Cities can 'sink' but for different reasons. Now in severe instances akin to what you're describing, you'll get settling. Prime examples of cities too heavy for ground support are Venice, Italy and New Orleans. The problem with those cities are that the founding citizens chose to build on marshy, wet land and that land, while initially able to support small populations, was not naturally capable of supporting large masses over the time those cities grew. They built on a mostly sandy, silty soil which alone doesn't provide a good foundation. Elsewhere, cities have a pretty good bedrock foundation and won't tumble or cave in suddenly.

Quicker means of this settling can occur through earthquakes which happen all the time, some more or less severe than others. You've seen those impacts, but those are usually do to tectonic action more often than settling action. In almost all historic instances, tectonic collision or separation have created more severe earthquakes than ground settling tremor magnitudes.

So the short of it is that you have no catastrophic sinking feeling to worry about and the measly holes we do make are hardly felt by the earth and are naturally corrected over time.

 

[TTEchidna]

It's like saying particles of dust will make your desk collapse. Big rock we're on, it's not going anywhere. I could understand maybe if it were hollow already and had no geological activity, like, say, Mercury, but Earth's heating itself underneath us. We're fine. It'd take a hell of a lot more mining than we've done in the history of mankind to collapse the entire crust.

 

[Jeff]

Here's some food for thought. If you had a giant scale, put all the humans on earth on one side, and all the ants on earth on the other, the ants would weigh more. So do you think that ants could cause something like that to happen with all their tunneling? If ants can't cause such a thing to happen, I seriously doubt humans can.

 

[$aturn¥oshi]

The continental crust is 20-30 miles thick. Do people even dig that far down?

 

[Drakon]

The continental crust is 20-30 miles thick. Do people even dig that far down?

No, the deepest mine is like 6 miles down.

 

[Cheesus Is Lord]

To give an idea of the scale of human activity compared to the size of the Earth, the deepest tunnel we've ever dug makes it about 0.3% of the way to the center. We have nothing to worry about. Also, shifting around material on the surface won't put excess pressure on the Earth, just shift its center of gravity by a ridiculously small amount.