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EAS 217 F20
EAS 217 Course Website for Fall 2020
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Global Impacts Video
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Posted by Josue on September 8, 2020 at 11:06 pmWhen it comes to measuring the movements of plate tectonics, how accurate are these measurements by using topography(on-site)? Did these measurements match satellite measurements?
-Josue Criollo
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I remember learning that Hawaii is located over a “hot spot” and that over time the islands grew with age as you go upwards. Can you explain in more detail how the Hawaiian volcanic islands actually formed? Are they located on-top of a divergent fault line? What type of tectonic activity is happening below those islands to make them so prone to volcanic activity?
-Gabrielle Belaya
Due to modern technology, the data provided by the remote sensing and geo-sensing satellites are very accurate. Because we use satellites new data is available within hours compared to physically collecting field data which can take months if not years.
-Shail Suthar.
Is this is a comment or question? Try to either pose a question, or click “reply” if you are commenting on a topic that someone else posted. Thanks.
Wow, great question! I did some research on the topic and based on my understanding found that unlike most islands Hawaii is not located near any plate boundaries, but rather the Pacific plate is moving over the fixed “hot spot” that is deep within the asthenosphere. Heat rises out of the “hot spot” from deep within the mantle and melts the overlaying lithosphere creating magma which pushes upwards to produce volcanism. As the Pacific plate moves over this “hot spot” the chain of volcanoes that we know as the Hawaiian islands is formed with the oldest Islands being furthest away from the “hot spot” and less volcanically active.
-Nechama Schneider
what are some models use to calculate plate tectonic movements? in addition what is the origin of subduction zone?
-David Xie
I learn that Pangea is the large continent before the formation of the seven continents. But why or how would earth form that large continent if there was all the plate moment of formation and destruction going on? Is there any model explanation on how Pangea first form?
-Zhi Hong Li
The earthquake graph in one of the videos was very interesting and got me thinking. I noticed that in certain parts of the world, earthquakes happen a lot more frequently. Why do earthquakes happen in clusters? Also, does the depth of the earthquake increase the intensity of an earthquake?
– Ronnie Reynoso
From the video related to plate tectonics, I found it very resourceful because it really shows the 3D version of Earth’s outer side and inner side. The 2 video’s message was clear and simple as it explained the process and movement of how plate tectonics really work and what causes it to diverge, converge or transform. From the 2 videos it really sums up the formation of Earth’s ocean, land and mountain. The main reason behind the movement of the plate and its process was the heat convection from the Asthenosphere (the upper layer of the earth mantle). I like how divergent and convergent are connected to each other as as the divergent plate moves apart and spreads further it leads to plate collides with one another which we get a convergent plate.
The second video talks about plate tectonic global impacts and I got to learn interesting stuff about the earthquake relations between plate boundaries. So, to determine plate boundaries I believed scientists connect to earthquakes plates which determine between old and new ages of plates. So, I guess Japan’s boundary is old and I was right because the deepest trench is the Mariana trench which is located near pacific ocean. At the end I was surprised that every year the Atlantic Ocean spreads at 1 and 2 cm per year but is it possible in future that it can spread in km?
These videos really cleared up a lot of my questions on plate boundaries, but one question I couldn’t stop thinking about is how the original Pangea era supercontinent formed in the first place? And also since all the plates are moving towards each other over millions of years will Pangea form again?
Both videos gave me a clear vision in regard with the plate tectonics’ dynamics. I will like to overview what I got from these videos.
Video 1 basically explains each type of plate tectonics.
Convergent, which pulls plates towards each other, is the responsible for the collisions within countries forming mountain chains and ridges. The less denser material at the subduction zone will sink and is normally seen that continental sediments will not sink while oceanic (depending on density) will.
Divergent, which pushes plates away from each other, is the responsible for separating countries, new ocean formation (seafloor spreading) and for new formation of rocks. This happens when hot magma emerges from the asthenosphere and and makes through the lithosphere as a volcanic activity form. As the oceanic lithosphere moves away from a spreading center gets older, thicker and colder.
Transform, which slides the plates past each other, can been seen as linear scar with steep cliffs, varying within each transform plate boundary. Transform faults in the oceans will break the ridges into fragments and are the site of massive earthquakes due to its location where large slabs of lithosphere are sliding each other.
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Video 2 goes in more detail whether plate tectonics behave at certain locations in the world.
In this video, the triple junction located in the Indian Ocean and around Red Sea is a phenomena that was totally unknown for me. Its pretty interesting since any plate boundary can be found and there is a trench at the junction.
I was wondering what happens at the trench of the junction?
While watching the second video, I found out that the fastest rate of sea floor spreading is 18 cm/year in the pacific. I had a very hypothetical question which is; would the earth still be inhabitable if the spreading rate in the pacific increased to 20 m/y and 10 m/y everywhere else? I mean I would think that if this happens the frequency of earthquakes would increase as well as volcanoes
Hello there! Your second question is something I always thought about also and apparently it is very likely that Pangea will form again because of the plates continuously moving. I actually researched your first question about how Pangea was formed in the first place and I found that there were supercontinents Laurentia, which included parts of North America, and Gondwana, which included Africa, Australia, South America, and the Indian subcontinent, that gradually merged together approximately 480 million years ago.
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When the continents were still together as Pangaea, the plates had separated it into the continents we know today. In the second video, at 9:29 the animation that plays shows two different plates being merged and creating the San Andreas fault, turning 2 convergent plates into one transform fault. My question being over a course of a few million years after the continents have formed another supercontinent, would the convergent plates somehow turn in divergent plates and separate the continents again? How does this process occur and over how long of a period?
With the plates constantly moving and seafloor spreading happening, were there more supercontinents formed other than Pangea, and is there an equation to calculate seafloor spreading?
-Gary Fung
These were very informative videos.
My questions are as follows – according to the Global Impacts video, the transform boundary that used to lie off the West Coast has now been absorbed by it. As time goes by, will this fault travel further inland into North America?
Also, given all these ongoing plate movements, will a new version of Pangaea eventually form?
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