Hey ya'll I'm back in Nashville and I just finished up that project I mentioned in my last post! Its pretty cool so ya'll better check it out, it's a Google Earth tour of the locations I visited on my tectonic cruise and of some other points of interest relating to tectonics. Make sure you read the info for the each of the places so you know their significance.
So check it out!
Love ya'll
Nancy
Sunday, April 10, 2011
Day 6
Day 6: San Andreas Fault (35°07'N, 119°39'W)
We just finished our last day in San Francisco and my cruise is officially over! I’ve had a great time and checking out the San Andreas Fault has been awesome. I learned all about how the 1906 San Francisco Earthquake was caused. The San Andreas Fault is a transform fault that’s about 810 miles long! It runs through California which is on the West Coast of the USA. It forms the boundary between the Pacific Plate and the North American Plate. The fault is plainly visible in the Carrizo Plain, in Southern Cali. This picture was taken by my friend I met on the cruise who decided to take a helicopter tour of the fault.
The transform fault causes lots of earthquakes because the two plates are sliding against each other. This map shows the direction of movement of the two plates
This fault doesn’t cause volcanoes or mountains, just a crack at the boundary and frequent earthquakes. Scientists say that the Southern segment of the fault is capable of an 8.1 earthquake that could occur up to just 40 miles away from L.A! It would kill thousands of people and cost billions of dollars. The earliest recorded earthquake along the San Andreas Fault was in 1680 and was of about 7.8 magnitude. The most recent significant earthquake was in January with a magnitude of 4.5.
The San Francisco earthquake of 1906 was of a magnitude 7.9 and resulted in a fire that is considered one of the worst natural disasters in the history of the United States. It was caused by a rupture on the San Andreas Fault, it rupture the northern third of the fault for a distance of 296 miles with a maximum surface displacement of about 20 feet.
This video shows the devastation caused by the earthquake and fire. It shows the city before and after the fire.
That was a really sad way to end by trip. =( but it was still really interesting and I had a really great time. I'm headed back to Nashville now and I'm working on a project that I will upload soon.
Love Ya'll
Nancy
Day 5
Day 5: New Zealand (41°S 174°E)
I haven’t gotten a chance to post about New Zealand yet, even though we’ve been here for four days! The longest time we’ve stayed at any one location. It’s probably because we had to sail for a really long time to get from Iceland to here because it’s all the way in the south-western Pacific Ocean. The Alpine Fault runs down most of New Zealand’s south island and forms a transform boundary between the Pacific and Indo-Australian plates. A transform boundary is when two plates are sliding past each other, this causes lots of earthquakes. We took a helicopter ride over the south island to look at the Alpine Fault, I took this great picture!
There are a TON of earthquakes in New Zealand. About 200 a year that are big enough to be felt by people nearby, though most of them are small (below magnitude of 5), usually about only one earthquake of a magnitude of 6+ per year. The Taupo Volcanic Zone is on the North Island of New Zealand and is a highly active volcanic area. Scientists believe it is so active because the earth’s crust below the zone is very thin (could be as little as 10 miles). The North Island is known for its volcanism and it is much less mountains than the South. Though most of the boundary is a transform boundary there is area in the South Island where the Pacific Plate has subducted beneath the Indo-Australian plate and created the Southern Alps.
This is a list of the sizable earthquakes in recorded history:
Map showing the Alpine Fault and the transform boundary:
Day 4
Day 4: Iceland (64° 01' N, 16° 41' W)
Our boat reached Iceland today! I’ve always wanted to come here so I’m so glad the Tectonics Cruise is stopping here. Though all the years I’ve dreamed of coming here I never imagined it was located at a very interesting spot in the world of tectonics. It’s actually located at a divergent boundary, meaning that the two plates are moving apart from each other and new crust is being created. When this occurs over land a rift is created and the land mass will eventually break apart and an ocean will be created between them when the surrounding water fills the gap. Iceland is breaking apart at the Mid Atlantic Ridge which is a divergent boundary between the North American and Eurasian Plates. This map of Iceland shows how the rift breaks up Iceland:
New crust is being created at the boundary but eventually the rift will become too deep and wide and the ocean will fill it. We got the chance to walk along the rift while we toured today; this is a picture of some of the people in my group during our rift hike:
Iceland is located in the North Atlantic Ocean and is very volcanically active. It is located over the Iceland hotspot and is one of the most active volcanic regions in the world. Eruptions happen about every five years. The eruption at Laki in 1783 caused a famine which killed almost a quarter of Iceland’s population. The most recent big earthquakes were in 2008 and 2000 thought there were no human fatalities many sheep were killed and injured in both earthquakes. I had a great time here, it totally lived up to my expectations!
Love Ya'll
Nancy
Day 3
Day 3: (0.37°S 91.55°W)
It took over a week of sailing for us to finally get here, but we arrived in Santa Cruz, the most populated of the Galapagos Islands, this morning! (The entire island chain only has a population of about 23,000) We had to travel all the way across the Pacific Ocean because the Galapagos are at the very eastern edge of the Pacific. I learned today that they are located at the northern edge of the Nazca Plate at its border with the Cocos Plate. On its east edge the Nazca plate borders with the South American plate. The Nazca plate is slowly moving south east away from the Cocos plate and into the South American plate. The Nazca plate is subducting under the South American plate. The Nazca plate is forced into the mantle, which is made of very tough and thick liquid rock. The outer parts of the mantle are coolest but as they near the center of the earth they become very hot and less solid. As shown in this picture:
The Nazca plate melts when it is forced into the hot mantle, then its melt products make their way up to the surface and create volcanoes. The Andes were formed when the South American plate crumpled and rose up over the Nazca plate, they are highly volcanic. This movement of the Nazca plate also created the Galapagos Islands. The Galapagos are thought to be produced by a mantle plume, which is a column of hot rock that rose from deep within the earth because it is hotter and less dense than surrounding rock. Scientists believe mantle plumes must originate from very deep within the earth because they stay still relative to each other over tens of millions of years even though the lithospheric plates above them move around. The plume burns through the earth’s crust and creates a underwater volcano which eventually grows to an island but because the Nazca plate is moving the island eventually moves off of the hot spot (the plume) which makes room for a second volcano to form and then this one moves making space for a third and on and on. In this picture you can see how the plate moves to the left after a volcanic island is formed and then a new one is formed:
Though the Galapagos are among the most active volcanoes in the world they are not very seismically active. Eruptions in the Galapagos have taken place in historical times on the islands, Fernandina, Isabela, Pinta, Marchena, Santiago, and Floreana. The island chain is expected to keep on growing and adding new islands, while some of the old ones will submerge into the sea. The most recent volcanic eruption in the Galapagos was in April of 2009 on Fernandina, one of the youngest islands. Check out this video of the eruption:
This picture shows Isabela from above, it’s one of the youngest islands.
I gotta get some sleep, it's been a long day! Will post again soon.
Love ya'll
Nancy
Tuesday, April 5, 2011
Day 2
Today I stayed on Saipan but continued my tour, I learned there are 11 major land volcanoes 9 of which are considered “active” and 42 submarine volcanoes on and surrounding the Mariana Islands. The Pacific Plate subducted beneath the Philippine Plate, this is because the Pacific Plate is denser than the Philippine Plate. (the reason for this is that the Pacific Plate is really big and so the crust material at its western edge has had millions of years to compact and become dense) Lots of earthquakes occur around the Mariana Islands because they are near a plate boundary; they occur because strain builds up along the boundaries and when the strain becomes too great the plates fracture and move causing earthquakes. The Mariana Trench is the deepest part of the ocean and the lowest elevation of the earth’s crust, at about 35,994 ft or close to 7 miles. It stretches 1,580 miles and is (on average) 43 miles wide. It’s almost 37 times as long as it’s average with! I learned some crazy stuff today; I hope the rest of my cruise is this interesting! Check out the pictures I got from the plate tectonics museum below…
This drawing shows how the subduction boundary works between the Pacific and Philippine Plates.
This map shows exactly where the Mariana Trench and the Mariana Islands are.
This is a vent at the Northwest Eifuku Volcano a submarine (underwater) volcano, formed along with the Marina Islands. It produces almost pure liquid carbon dioxide and is one of only two in the world.
Will post again soon!
-Love Nancy
Day 1
Day 1
Saipan, Mariana Islands (15°10’51”N, 145°45’21”E)
When my BFFL Kristy suggested I try doing the same “tectonical” cruise as she took a couple of years ago I was totally skeptical. I mean a science cruise? I never expected it would be this interesting, and fun! I’m going to visit all of these new and super exciting places, like today our boat landed at our first stop, Saipan, one of the Mariana Islands located in the western edge of the Pacific Ocean. The beaches are beautiful, especially because the whole west side of the island is surrounded by an offshore coral reef, so there’s a huge lagoon! Though the beaches are great I spent most of my day on a Tectonics Tour provided by the cruise! Apparently, the whole chain of Mariana Islands was created when the Philippine Plate and the Pacific Plate began pushing towards each other (AKA converging). The boundary between these two plates is called a subduction boundary because one of the plates is forced beneath the other. (FUN FACT! The “sub” in subduction means below!) At subduction boundaries like this one, long deep trenches are formed. (called deep-sea trenches) When a trench is formed a volcanic island arc is also formed. The Mariana Islands are one example of volcanic island arc and their accompanying deep-sea trench, the Mariana Trench. I learned so much interesting stuff, and that was just the first part of my tour! I’ll update tomorrow with more info!
Check out this picture i took myself off of our ship of the two volcanoes on the island of Anatahan, one of the central Mariana Islands. Its first eruption in recorded history was in 2003, it is the most recently active volcano of any in the Mariana Islands.
I miss Nashville but i'm having a great time!
I miss Nashville but i'm having a great time!
Love Ya'll
-Nancy
-Nancy
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