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  • You've seen politics and national borders change all the time, but

  • have you ever witnessed a continent literally breaking apart?

  • Well, it's possible, and it's happening to Africa right now.

  • In 2005, a 60 km (37 mi) long stretch of the continent

  • cracked open over a period of just ten days,

  • and it hasn't stopped expanding since.

  • Eventually, the landmass will break right off,

  • giving birth to a brand new ocean.

  • This is WHAT IF,

  • and here's what would happen if the African continent broke apart.

  • The face of our planet is continually changing,

  • thanks to the shifting of tectonic plates,

  • but it's rarely this noticeable.

  • In the years since 2005,

  • more cracks in the Earth have opened up

  • in several countries throughout the African continent,

  • sparking fear among their populations.

  • But as scary as the fractures may seem,

  • experts say they could teach us a lot about how our world was formed.

  • Have you ever heard of the East African Rift?

  • Neither had most people in Ethiopia until the ground started cracking beneath their feet.

  • The East African Rift is an active continental rift zone in East Africa,

  • and judging by the blank look on your face,

  • it may require more of an explanation before we go any further.

  • Okay, so the rigid outer layer of the Earth is called the lithosphere,

  • and it's broken up into many tectonic plates.

  • Tectonic plates are basically large slabs of solid rock

  • that move relative to each other at varying speeds.

  • When these plates move apart from each other,

  • they cause fractures to be formed at their boundaries.

  • The land remaining in between the two plates starts to sink,

  • and forms what's known as a rift valley.

  • This can lead to new boundaries being created between plates.

  • In the case of the East African Rift,

  • the African tectonic plate is breaking up

  • into two smaller ones: the Somali and Nubian plates.

  • So what happens when these plates completely break off from each other?

  • Well, for one thing, we won't be around to see it.

  • Despite the rapid appearance of the surface cracks,

  • geologists say the continent won't fully break apart for about 10 million years.

  • As the plates continue to pull away from each other,

  • the rift valley will sink deeper and deeper,

  • and water from the Red Sea will flood in to create a new ocean.

  • Africa will become a lot smaller,

  • as parts of southern Ethiopia and Somalia will drift off to form a new island.

  • What does this mean for all of us in the meantime?

  • Well, African residents who live along the rift can expect more disturbances:

  • cracks through their highways and cities,

  • and the emergence of vast canyons where there weren't any before.

  • But it's not all bad news;

  • in fact, most geologists are pretty excited about studying the whole process.

  • They believe it can lead to some pretty "groundbreaking" information

  • about how our Earth's surface is shaped,

  • and how earthquakes and volcanic eruptions work.

  • One day all of our continents will look completely different,

  • but that's a story for another WHAT IF.

You've seen politics and national borders change all the time, but

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B1 中級

如果非洲大陸分裂了怎麼辦? (What If the African Continent Broke Apart?)

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    林宜悉 發佈於 2021 年 01 月 14 日
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