I understand that the Panama Isthmus is necessary for the Gulf Stream, but what would happen if instead of a solid land bridge, like shown below, it was radically changed into a series of islands during the 1st century due to an earthquake? How dramatically would it change the world climate?

Edit: The earthquake was magical one, so not the natural flow of tectonic plates.

enter image description here

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    $\begingroup$ I think you would benefit from rephrasing this as "the cratons of North and South America drifted apart, leaving an ocean gap between them." This is a higher order occurrence than an earthquake, and would result in a lot of earthquakes over a period of millions of years. You can't just have this happen due to a single event. $\endgroup$ Aug 28, 2023 at 4:09
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    $\begingroup$ It would dramatically reduce the sea transport carbon footprint :) $\endgroup$
    – fraxinus
    Aug 28, 2023 at 10:09
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    $\begingroup$ Interestingly. this would probably have very little impact on travel between North and South America because the Darién Gap is already more dangerous and difficult to cross than a Panamanian archipelago likely would be. $\endgroup$ Aug 28, 2023 at 11:11
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    $\begingroup$ @AustinHemmelgarn It would however have greatly accelerated the development of the west coast of both the Americas. No need to brave the Oregon trail, hack through Malaria-ridden jungles or take the long, icy route around Cape Horn. Just a (relatively) safe and quick boat trip through the long settled Caribbean. $\endgroup$
    – mlk
    Aug 28, 2023 at 14:11
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    $\begingroup$ @fraxinus not that obvious: if shipping was easier and cheaper, there may actually be even more of it: en.wikipedia.org/wiki/Jevons_paradox $\endgroup$
    – njzk2
    Aug 28, 2023 at 19:55

2 Answers 2


It would not change that much.

it was radically changed into a series of islands during the 1st century due to an earthquake

This description points to a situation where the landmass we have today would be replaced by islands separated by a rather shallow sea. Which is similar to the configuration at the strait of Gibraltar.

In that situation the oceanic currents have a hard time flowing, meaning that there would be a weak connection between the Atlantic and the Pacific.

As a consequence, there would be a limited impact on the climate, as the global oceanic circulation would not be drastically altered.

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    $\begingroup$ The Isthmus is based upon a shelf uplifted by a subduction zone to the west and a collision with South America. The sea water flow was greatly reduced prior to land appearing above the waves. Letting the land sink below the waves wouldn't change things much. science.org/doi/10.1126/sciadv.1600883 $\endgroup$
    – David R
    Aug 28, 2023 at 14:13

A frame Challenge.

The theme song of the tv series Land of the Lost, 1974-1975, told how the protagonists were transported to a weird sort of pocket universe by "The Greatest Earthquake ever known".


As I remember, Geologists long ago debunked the idea of an Earthquake powerful enough to sink a continent like Atlantis. Of course what you are asking for would be the sinking of much smaller area and possibly for a much shorter distance.

So possibly we need to find out the largest area ever subsisted in any recorded earthquake, and the deepest that any recorded earthquake has ever subsisted any land.

I think that a major earthquake might drop land in an area of several hundred or thousand square miles (an area probably only tens of miles on its longest side) about a meter or so.

So maybe something else could sink sections of Panama.

I guess an asteroid impact could vaporize many mountains in Panama, instantly lowering the ground level to below sea level.

As to how that would change history, it would exterminate the human species and all other large lifeforms, a significant historical change.

It would be more plausible for a group of super advance extraterrestrials to decide they want to excavate a sea level panama canal, and make it much wider and much deeper than necessary for even the largest plausible ships to navigate through.

Possibly the aliens have records of the oceanic currents and biology from before the Panama region closed the gap between the Pacific and Atlantic oceans, and wish to recreate the species of whales and sharks (megaladons) which inhabited it.

Possibly the intent of the aliens may also be connected to the thousands or millions of cubic miles of rock their worker robots will excavate, and the islands or mountains they might build with that rock.

  • $\begingroup$ The major faults of the Panama plate are an uplift fault on the border with the Caribbean plate and a transverse fault on the border with the Nazca plate. Neither of these faults is the sort that produces much vertical motion. If you want to rapidly sink a section of Panama, you need to somehow transform one of them into either a rift zone or a subduction fault. $\endgroup$
    – Mark
    Aug 28, 2023 at 23:03
  • $\begingroup$ Grabens can occur where a "strike slip" fault has a bend. The section in the middle of the bend falls down and gets filled with sediment. Other deep valleys happen during extension where blocks get tilted (see the Grand Tetons - the valley in front of the range is very deep and filled with sediment). Neither is currently part of Panama geology. The transverse fault is out in the ocean and the trench there is inactive. $\endgroup$
    – David R
    Aug 30, 2023 at 14:19

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