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.

Kathmandu, Nepal - Collision

I'm feeling cramped and tired but I've finally touched down in Kathmandu, Nepal.  Nepal is right between India and China so it's just a little south of being right in the middle of Asia.  The coordinates of Kathmandu are 27°42'N 85°20'E. I caught a cab to the hotel, checked in, lounged in the hot tub, and then went to bed.  In the morning I woke up for an early stroll to get to know the area.  I stopped by a street vendor a purchased some delectable fruits.  Then I went out for brunch and feasted on some traditional Nepalese food,Tibetan Momo and Dal-bhat-tarkari. 

The beautiful pool with an amazing view of the mountains at Radisson Hotel -

Tibetan Momo -

Dal-bhat-tarkari -

Mt. Everest, the tallest mountain in the Himalayas, and in the world -
Many people come here to look at the view of the gorgeous mountains, go on fantastic hikes, and even to try and attempt to climb Mt. Everest and other deadly mountains.  What they don't realize is how these amazing geological features came to be.  Again, it's all thanks to the tectonic plates. 

Diagram of a collision boundary -
When two plates of the same or very similar densities (oceanic/oceanic or continental/continental) move towards each other they collide (hence collision boundary).  The two plates collide and since they are of roughly the same density they force each other upwards. That's how mountains are created.  In the case of the Himalayas, the Eurasian Plate is sliding South West and is colliding with the Indian Plate which is sliding North East.

Collision boundaries only form mountains.  They don't form volcanoes because none of the plates are subducting under the other and being melted into magma like what happens at a subduction boundary.

The Indian and Eurasian Plates are still moving towards each other and with every sudden movement an earthquake occurs.  Because of this earthquakes happen quite frequently.  Similar to the San Andrea's fault, many of these earthquakes have either had too small of a frequency or they've too deep in the Earths' crust to be noticed by humans.  A well-known earthquake occurred in 1933 which killed thousands in both Nepal and Northern India.

The most recent large earthquake happened on September 18th, 2011.  The Sikkim earthquake, as it's called, lasted from 30-40 seconds and killed at least 111 people from five different countries.  The majority (97) of the deaths were from people living in India.  It had a magnitude of 6.9.

Tuesday, April 3, 2012

Los Angeles - Transform

After 10 hours the great skyline of LA was in sight.  My flight finally landed in the Los Angeles International Airport.  It felt good to be back in the Unites States.  Los Angeles is in California which is located in the western part of North America, or more exactly, at 34°03'N 118°15'W I hurried through the airport and caught a taxi to my hotel.  Although I have always lived relatively close to California I've never actually been there so I'm excited to finally see what it's like! 

Los Angeles International Airport -

Hotel Shangri-La Santa Monica -

I arrived at the swanky, five-star Hotel Shangri-La Santa Monica and was eager to hit the hay.  It's surprising how tiring traveling is!

Natural History museum of Los Angeles County -

I woke up and had a quick meal consisting of instant oatmeal with brown sugar and an assortment of berries and then I left for the Natural History Museum of Los Angeles County.  I was really excited to see what I could further learn about tectonic plates.

Was it luck that I happened to choose LA as one of my destinations because it happened to be right next to a different kind of tectonic boundary, a transfrom boundary.  I learned that at a transform boundary two plates of equal or near equal density go in opposite direction so that they "pass by" each other instead of going towards or away from each other.  This is depicted in the picture above.  In this case the Pacific Plate and North American Plate are sliding by each other (LA is on the Pacific Plate).

Diagram showing the San Andreas Fault running through almost all of western California -

Bird's eye view of the San Andreas Fault -

From this particular movement of  tectonic plates, transform boundaries like the San Andreas fault make geological features resembling valleys, or more simply, giant cracks in the ground.  The San Andreas fault is over 800 miles long and is 10 or more miles deep in the Earth's crust in places.

Because none of the plates are subducting under the other there aren't any volcanoes but there are many earthquakes.  When pressure builds up and the plates make a sudden movement an earthquake occurs.   Thousands of small earthquakes occur in California every year although the vast majority of these have such low frequency and/or they're so far underground that we can't even notice them. 

Some earthquakes are massive though.  The largest recorded earthquakes along the San Andreas fault occurred in 1857 and 1906.  The large earthquakes that took place in these years had a magnitude of around 8, which is incredibly big!  From the earthquake on January 9th in 1857 and other more minor earthquakes in the year the plates moved around 30 feet! On April 18, 1906 the massive earthquake mainly in the San Francisco area caused a fire and all together 700 lives were lost.

The two most recent earthquakes created by the San Andreas fault occured in 2011.  One happened on January 7th in San Jose  and the other on January 12th in the small city of San Juan Bautista.  Both of these earthquakes measured a little over a magnitude of 4.

Well LA and the San Andreas fault are both so interesting but I did some research in my hotel room and I decided on my next destination... Kathmandu, Nepal, which is in the midst of probably the most famous collision boundary, and of course, the Himalayas.

Tokyo - Subduction

I'd heard a lot about the vast and grand city of Tokyo so I decided that that would be the first destination of my worldwide adventure.  Tokyo is in Japan which is located in the very eastern part of Asia, or more exactly, at 35.6833° N, 139.7667° E.  I left my hometown city of Seattle and caught a flight to Tokyo in the Sea-Tac international airport.  After roughly 14 hours I finally arrived in Tokyo at dusk.  As my plane started descending I watched the bright city's skyline and thought how it made Seattle look puny. I landed in the Narita International Airport and caught a taxi to my hotel.

Narita International Airport -

Hotel Metropolitan -

I arrived at the elegant Hotel Metropolitan and I was eager to get straight to bed after a very long 14 hours in a plane.  In the morning I had a monstrous breakfast which consisted of fried eggs, pancakes, sausage and orange juice.  Next I wandered the busy and bustling streets of downtown Tokyo, as tourists do, feeling small and not exactly sure what to do and where to go.  I walked by the National Science Museum and decided to take a peek inside.  

National Science Museum, Tokyo -
There was so interesting stuff in that building. I could have spent the entire day there!  I learned many things but the most interesting thing that I learned was about Tokyo itself.  I learned that Tokyo's geographical location is right next to a subduction boundary.  I had always wondered how geographic features such as volcanoes and trenches were made and now I know.  In this case the oceanic Pacific Plate is subducting under the Okhotsk Plate (Tokyo is on the Okhotsk Plate).

As depicted in the picture above, when two tectonic plates (one continental and one oceanic) move towards each other multiple things happen.  The denser, oceanic plate (the oceanic Pacific Plate in Tokyo's case) goes under the less dense, continental plate.  As the oceanic Pacific Plate sinks further and further into the earth it heats up more and more until much of it melts and turns into magma. 

Mount Meakan -

This magma is very hot and less dense than its surroundings so it travels back to the surface of the earth.  This creates enough pressure to let the magma force itself through the other plate (the Okhotsk Plate in Tokyo's case).  This process is what creates volcanoes.

I decided to visit one of Japan's fabulous volcanoes, Mount Meakan (photo above). It's an active volcano an it's last eruption was on the 31st of March in 2006.  Am i ever glad that it didn't erupt when i was there!

Mount Meakan is one of the 108 active volcanoes in Japan.  47 volcanoes are remarkably active and on average there are about 15 volcanic events every year.  The most recent volcanic eruption in Japan was when Sakurajima erupted on the 26th of February in 2012.  Here's a video that depicts the eruption:

The dark blue in the photo above depicts the under-water trenches that are being created by the oceanic Pacific Plate subducting under the Okhotsk Plate -

Subduction zones also create impressive trenches.  The picture above shows a vast underwater trench created by the oceanic Pacific Plate subducting under the Okhotsk Plate.  Trenches are formed right where the continental plate starts to "overlap" the oceanic plate by subduction as I told you about before.  

Damage caused by earthquakes in Japan -

Unfortunately, where there are subduction zones, there are earthquakes.  These earthquakes are caused by the incredible amount of friction that is created by the two plates moving towards each other.  Earthquakes happen quite frequently, in fact a 4.4 Magnitude earthquake hit Hidaka-chiho Seibu, Japan just yesterday (April 21st, 2012).

Well enough of Tokyo and lovely Japan.  I decided that I love visiting these tectonic boundaries so off to my second destination, Los Angeles! 

Introductory Page

Hi, I'm Cory!  As you can tell in the photo above I'm an astronaut.  Going up into space is getting pretty boring so I decided that I want to travel the world instead.  In this blog I will talk to you about four of the places that I visited.

*Disclaimer*  This is a fictional blog intended only for the purposes of my Earth Science Class.  Please read with that in mind.  Thank you!