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Does the Mohorovicic Discontinuity subduct under the upper crust as the tectonic plates shift? If it does, why can't a Mohole be used as a dump for the world's most dangerous radioactive waste? I realize that drilling such a hole was given up years ago as too expensive, but the disposal of dangerous waste is such a worldwide problem that all advanced nations ought to be willing to share the drilling costs.

This is a good question and a great idea. Unfortunately, there seem to be a couple problems with your proposal. The first has to do with the reasons for the termination of the efforts to penetrate the Moho by drilling. The way I understand it, the Deep Crustal Drilling Program was suspended because of an inability to continue (due to the extreme heat and pressure found at depth), and not because of financial considerations. Therefore, it is probable that we will not be able to access the Moho by drilling. Technical advances may solve this in the future, but for now it just cannot be done.

I heard about efforts in the 1960s to investigate using the subduction of the lithosphere to accomplish exactly what you propose - dump the nastiest stuff into a subduction trench and let the earth recycle it. A great concept! Apparently, 2 divers were sent down into a deep trench in a high pressure diving bell to check it out. According to my sources, they found so much life down there (even in the deepest of the deep), that the idea was scrubbed. And it was probably for the best - the rates of subduction are so slow that any container we could put the stuff into would probably decompose (or be crushed) long before it was deep enough to effectively remove the waste products from the surface environment.

Keep thinking - someone's got to come up with a solution to this real soon or we (as a global community of interrelated species) will be in very deep trouble.


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