
Large crack in East African Rift is evidence of continent splitting in two - lovelearning
https://theconversation.com/large-crack-in-east-african-rift-is-evidence-of-continent-splitting-in-two-94056
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mrfusion
Wild eyed idea. Could we run a cable across this. Have it turn a gear. Then
gear it up to a one million to one ratio and turn a giant generator with the
motion?

Free continental drift power?

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marshray
I love this idea, but the speed of separation is just a couple of cm per year.
Unless the cable had absolutely no temperature expansion, weather changes
would probably have a far greater effect on cable length than the
imperceptible drift of the endpoints (which suggests another crazy idea
interesting in its own right).

One might build this deep underground to minimize temperature changes and
provide the hard rock anchor points necessary for the forces involved.

~~~
sannee
> weather changes would probably have a far greater effect on cable length
> than the imperceptible drift of the endpoints (which suggests another crazy
> idea interesting in its own right)

There is a clock running for over a century based on a similar idea:
[https://en.wikipedia.org/wiki/Beverly_Clock](https://en.wikipedia.org/wiki/Beverly_Clock)

~~~
userbinator
...and the commercial version, which is still in production:

[https://en.wikipedia.org/wiki/Atmos_clock](https://en.wikipedia.org/wiki/Atmos_clock)

Not cheap (few k$), but not as expensive as some other high-end timepieces
either.

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vmarquet
lemonde.fr published an article [1] yesterday, in which they debunk this news.
A seismologist at Southampton University says [2] that it's unrelated to the
rifting.

[1]
[https://www.youtube.com/watch?v=4QJ8MmbAC_o](https://www.youtube.com/watch?v=4QJ8MmbAC_o)
(in French)

[2]
[https://twitter.com/seismo_steve/status/977258571716091904](https://twitter.com/seismo_steve/status/977258571716091904)

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xbryanx
Lots of people don’t realize that North America almost did this same thing
about a billion years ago. Check out the failed rift zone called the
Midcontinent Rift. Ever curious why Lake Superior is shaped like that? MCR
ground zero.

[https://en.m.wikipedia.org/wiki/Midcontinent_Rift_System](https://en.m.wikipedia.org/wiki/Midcontinent_Rift_System)

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lainga
Does this also explain the extended butte-and-valley terrain in the Southwest?

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njarboe
The butte-and-valley terrain, as you called it, is more from the uplift and
slow erosion of a large area called the Colorado Plateau. The various
sediments deposited on and off over a billion years or so have different
erosion rates. When a thick, more weatherproof, sandstone overlies a more
erodable shale you get those big cliffs and buttes.

The area covered by Nevada, on the other hand, is being pulled apart over the
whole state. This creates what is called a basin and range topography. The
extension is mostly east-west and you can see the ranges and valleys mostly
are north-south due to this. Lots of geothermal there as the spreading rock
allows hot rock from below to move close to the surface.

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phyller
Does anyone else think this is just erosion in the soil due to heavy rain?
That's probably too boring of a story though. I think an earthquake that
pulled the land apart that wide would be a major news event.

~~~
ams6110
Seems very plausible. Roads in my area are currently full of wide cracks and
holes that appeared seemingly overnight, as happens every spring.

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tomcooks
It's not evidence of continent splitting but of soil erosion, much like what
is happening in Rome[0]

[0]([http://www.lastampa.it/2018/02/14/italia/cronache/roma-si-
ap...](http://www.lastampa.it/2018/02/14/italia/cronache/roma-si-apre-una-
voragine-in-strada-e-alcune-auto-vengono-inghiottite-
XpaU13uOgyKJewE0jOyThN/pagina.html))

~~~
edf13
Probably not...

> and was accompanied by seismic activity in the area.

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rplnt
Was this a sudden shift of several feet on the ground level (because the
underlying ground was in tension for years)? Or how does a crack that big
form? Is it even as big as the hole? I.e. if we were to measure from two
points across the crack - did they move as much as the crack is wide?

Who would own the new land?

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smoyer
"the South Atlantic ocean, which resulted from the break up of South America
and Africa around 138m years ago – ever noticed how their coastlines match
like pieces of the same puzzle?"

No I had not but now that I look at it it's so obvious. And wow!

~~~
blattimwind
Alfred Wegener noticed this about a hundred years ago and formulated that
theory around this observation and some supporting evidence. However, until
the 1950s and 1960s the _why would they be moving?_ was wholly unanswered and
Wegeners theories were not accepted until then.

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kzrdude
It's remarkable how young that understanding is

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hyperpallium
If it's rift due to plate separation, wouldn't the crack go down all the way
to the mantle? Not the 20-30 feet seen in the video.

~~~
lisper
It does, but in general when a rupture opens up at the surface, the side walls
fail quickly and fill it in with loose material. It is only when a surface
rupture is "fresh" that it looks as dramatic as this.

~~~
hyperpallium
Sure, the side walls fall in... but wouldn't that happen more easily near the
surface, with loose topsoil, than for deeper rock? Meaning, that if the top
part hadn't fallen in yet, the lower parts wouldn't have either.

Perhaps pressure with depth is a factor, tending to press the sides together.
Amd the deeper material might not be rock, but e.g. sand or other loose
material.

~~~
lisper
There isn't just one well-defined crack. Where the plates are separating there
is a whole zone of material that is being pulled apart and cracking open. The
current crack is just one of many many fissures in the rift zone. And the
individual fissures are jagged and ziggy-zaggy, so even if they had clean
sidewalls you still couldn't see straight down to the bottom.

Also, the crack is not filled in all the way to (near) the top. There are gaps
and voids all the way down. The "bottom" that you see is just the first
filled-in part. If you dug down you'd probably find more gaps. (I'm not 100%
sure about this. I know about the mechanics of slip-strike faults because I
live in California within walking distance of the San Andreas, but the African
rift is different so I could be wrong about some of these details.)

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_rpd
This well known process, which will play out over tens of millions of years,
appears to be receiving media attention because ...

> A large crack, stretching several kilometres, made a sudden appearance
> recently in south-western Kenya. The tear, which continues to grow, caused
> part of the Nairobi-Narok highway to collapse and was accompanied by seismic
> activity in the area.

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mirimir
There was a previous flurry of media attention about the extreme geology in
Djibouti and Ethiopia.

[https://www.theguardian.com/world/2006/nov/02/travelnews.tra...](https://www.theguardian.com/world/2006/nov/02/travelnews.travel)

