Is it possible to alter plate tectonics?

Question

Is there a way to split a tectonic plate into two plates? or a way to alter their motion?

-What would the impact of a such a change up here on the surface? I know that plate tectonics is run by giant convection currents in the mantle so is there some way to change those?

Assume infinite resources and advanced technology but still within the constraints of the laws of physics.

I was thinking about re opening the western interior seaway or a chain of islands across the Atlantic or something in a few million years

Answer 1

The forces involved with plate tectonics are so large in scale that altering them by, say, splitting a plate in two would require a massive amount of energy. That's not necessarily the main problem. The actual issue is what happens when such forces are exerted on surface. Massive tearing of the crust could potentially require (or subsequently cause) a near-extinction level event. Then you're also opening fissures deep into the earth, surface buckling, tectonic releases of stress (earthquakes, tsunamis, etc.) and potentially altering global weather systems. Basically, there's a reason people who try to do this are universally the supervillains in stories: there's no way it ends up pretty for humanity. Or life on earth in general.

It's far easier and safer to make islands through depositing material on the surface (and carving canals) then to alter the underlying plate tectonics. We already do that at the present.

Answer 2

Nothing within our current technology or knowledge of the plates (we have a pretty minimal grasp on what processes drive these plates and more of a bunch of assumptions that kinda seem right anyway). This isn't to say it isn't possible and we can't speculate a little on what could do it...

The biggest issue to get around isn't just the size and magnitude of the energy that these moving plates have, but also the timeline they operate on. They literally move just inches a year...over a geological time scale, it's actually kinda quick, but to us humans this change is so subtle that we can't perceive the motion. As your question properly states : "something in a few million years"...and therein lies the problem. Whatever is changing the motion also has to act over this multi-million year timeframe, or the changes would be abrupt enough that our world on the surface would be destroyed by massive earthquakes beyond what we've ever seen. I guess the first question presents itself as 'who alive now would possibly care what state the world is in 1 million years from now, and more-so why would they invest time and energy now to change something 1 million years from now?

The other issue here is the plates interact. To move one plate in a different direction would either need to push another plate in a different direction as well, or require two plates to push further together. Altering a single plates motion might create entire mountain ranges elsewhere (over the million of years time scale of course).

Unfortunately I can't imagine much for means to do this. Id suggest to you that a type II civilization on the Kardashev scale would be the minimum requirement to undertake such a feat.

(complete side note, but I'm getting a laugh from spell check changing Kardashev to Haberdasher)

Answer 3

It is too broad to answer about tectonics as a whole for me, but a good power blast may help you in your hypothetical (I hope) task. The history/mythology of nuclear weaponry shows that the blast of the Tsar Bomba was nearly enough to fracture the Earth's crust like a nut.

Answer 4

If we assume that infinite resources includes large enough amount of time, then sure with sufficient understanding of the underlying physics and enough computing power and understanding of the current state of affairs it should be possible to split a tectonic plate or alter ones motion. Altering the motion seems to be the easier of the two as that just requires having someway of influencing the mantle convection where as splitting would seem to require more information and power over things.

From the surface perspective it as with all plate motion, there would be earthquakes and quite probably volcanos involved so that if the time scale was short things would be very, very bad for anything then alive and possibly life in general. Consider that small movement of plates currently cause massive earthquakes and tsunamis, and you are talking about major movements which if all of that energy got released at once would be absolutely devastating.

To contradict alex's response, Tsar Bomba only was a 8.35 on the Richter scale. The Sumatra earthquakes of 2005, 2007, 2012 come from a movement of that plate of 2 inches per year, all of those being much larger than Tsar Bomba in energy release. Were say the western interior seaway to be created at once that would involve obviously a release of energy many multiples of times greater and would not be fun to be around; or quite likely survivable to be around.