Wednesday, April 4, 2012

Ascension Island - Divergent

Here I am on the Ascension Island.  It's only 34 square miles and  it has a population of only about 880 people.  It's in the middle of the South Atlantic Ocean. 

Location of the Ascension Island.  Coordinates: 7°56'S 14°25'W -

Map of the island -

 I pitched a tent and spent most of my first night staring at the starry sky. 

The sandy beach and blue water of Comfortless Cove -

The next day didn't have a cloud in the sky and I spent most of the day on the sandy beaches of the island.  The sand is surrounded by dark volcanic rock.

Diagram of a divergent boundary -

You might be wondering why I chose to come to such an obscure place but it's because the Ascension Island is in a very exciting geological place.  The Ascension Island is right in the middle of the Mid-Atlantic Ridge which is a divergent boundary.  A divergent boundary is where both of the plates are moving away from each other as depicted in the diagram above.  The Ascension Island is right in the middle of the African and South American Plates moving away from each other.  Underwater divergent boundaries create new oceanic crust, under-water volcanoes, sub-marine mountain ranges, and deep-sea vents.  On land divergent boundaries create normal faults, rift valleys, and some volcanic activity. These geological features are created because magma comes out of the "crack" that's created from the plates moving apart.  

Lava Fields -

I took some very enjoyable hikes through the large lava fields.  These rocks were created by the magma which filled the gap between the splitting plates. 

Green Mountain -
There aren't any volcanoes on the island but there are many along the Mid-Atlantic Ridge underwater.  There also haven't been any earthquakes directly on the island.  The most recent one that impacted the island happened on April 9th, 2012 just north of the island.  It measured at a magnitude of 5.8.  Earthquakes happen at divergent boundaries when plates make sudden movements which send vibrations into the crust.    Within the last two years there have been four earthquakes that effected the Ascension islands.  All of which were measured at a magnitude of 5-6.

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