I am writing a book where prior to the current events, an event caused by a magic surge resulted in the Somalian tectonic plate to be quickly lifted directly up enough to create a new continent. I was wondering what end results would occur from this event.

I already believe tsunamis would occur but I do not know what areas would be affected, the number of casualties, any species going extinct (maybe lemurs) and any other possible natural disasters or less serious events. I would also like to know if this new "continent" would still be attached to Africa.

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    $\begingroup$ Answer: So much energy is released that the earth's surface liquefies and all life on earth ends. If you wait long enough someone below will do the math to verify. $\endgroup$ – SurpriseDog Dec 30 '20 at 2:42
  • $\begingroup$ Lifted by how much? 5 metres? 5 kilometres? Do you know what’s the difference between ocean crust and continental crust? And that it’s not simply an issue of elevation? $\endgroup$ – Gimelist Dec 30 '20 at 2:44
  • $\begingroup$ @Gimelist It would probably be lifted 7.5 kilometres. $\endgroup$ – Justin T Warner Dec 30 '20 at 3:02
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    $\begingroup$ How quickly is "quickly"? If the answer is faster than "a hundred thousand years", then yes, what @SurpriseDog said. All life on earth would end. $\endgroup$ – jdunlop Dec 30 '20 at 4:25
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    $\begingroup$ A couple minutes, for 7km elevation of 45925000000000000 tonnes of rock. Disregarding the energy source. You would create a 15-35 km high tsunami IN THE BEDROCK of the crust surrounding this craton. I expect any settlements on the MOON will be pulverized by the tiny fraction of debris( a few trilion tons, if that much) that reaches escape velocity. You will get sued by Lucasfilm, erm. Disney, for stealing their "Alderaan" scene from StarWars. $\endgroup$ – PcMan Dec 30 '20 at 14:44

Moving That Much Mass Introduces Energy

The area of the Somali plate is 16.7 M square km. Assuming you were raising the plate by 1km in the space of three months, using the most conservative values you provided in comments, how much energy would be released?

1 km in 3 months is about 0.15 mm/s. (For comparison, its current velocity on the mantle is 6mm/year.) Because magic is involved, we'll assume it doesn't bind with any adjacent plates and cause world-ending earthquakes off the bat.

Assuming that more stone is being magically conjured to fill the gap created by the rising kilometre of rock, you just need to accelerate 16.7M cubic km of (for simplicity) granite to 0.15 mm/s.

This works out to energy expended ~= 5.5 * 10^15 J/s. That's a little more than a megaton of TNT equivalent... every second. For three months. 7.8 million megaton bombs. To say that this dwarfs the nuclear arsenals of the planet is to radically understate the problem.

This, again, assumes that magic is dealing with crustal collapse and other calamities. Just moving that much mass is going to introduce an enormous amount of energy into the environment. If you're already using magic, why not just have it poof the plate into its new position, removing all the matter that would be in the way? You'd murder everyone in Madagascar and the east coast of southern Africa, but it would save a lot of headaches.

  • $\begingroup$ I appreciate this suggestion, however, it would require some handwaving as the magic system is more based around transmutation than conjuration. Thank you for your help. $\endgroup$ – Justin T Warner Dec 30 '20 at 9:57
  • $\begingroup$ @JustinTWarner: Would it be appropriate, for your transmutation, to change all the water above into rocks, then, instead? It would result in the Somalian tectonic plate appearing to have lifted up, but would not move mass as much, so less energy at play. $\endgroup$ – Matthieu M. Dec 30 '20 at 13:13
  • $\begingroup$ @MatthieuM. Sorry, I guess just stating transmutation was misleading. This power is part of a sub-system of my magic system called "Earth," like Earth-Bending from Avatar, the Earth system is above moving Earth. However, Earth does have a spell called "Bullet" which can create a stone bullet and fire it in a direction desired by the caster, or just fall down otherwise. Considering this event was an event where a character had too much magic within them and had to expel it all or die, the spell could create enough rock to make a continent. But water cannot be turned to rock. $\endgroup$ – Justin T Warner Dec 30 '20 at 20:11

7.5 km is deeper than the crust in places, so magma would flow across the surface for centuries, coving hundreds of thousands to millions of square kilometres. Which is how the Ethiopia-Yemen igneous province formed. This would likely have a devastating effect on the climate and environment: the Deccan Traps degassing is linked to global marine mass extinction.

In time new islands might form along the oceanic plate boundaries.

  • $\begingroup$ Fair enough, would 1 kilometre be better? $\endgroup$ – Justin T Warner Dec 30 '20 at 4:33

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