Global Impacts Video

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.

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

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?

The videos for me were very interesting. It was a mix of reviewing the basic concepts and ideas we learned in class and previous lectures, and finding out new things that I didn’t know. For example, I always thought that any plate boundary would be hot because of the activity itself characteristic of every boundary. But in the “Plate Tectonics Basics” video is mentioned how the crust could be hot or cold in a convergent plate boundary.  It didn’t make sense to me that the crust could be cold considering there is melting happening in this type of boundary. But I understood later that it does make sense since this melting is occurring several meters down while is subducting under the other plate, and is cold on top since the crust would be several kilometers away from the hot divergent boundary/oceanic ridge it formed in the first place.

Now, is the second video “Plate Tectonics Global Impacts” that mentioned hot spots and it remembered me about a daily doubt I have with the subject. The most common example to explain hot spots is Hawaii and the chain of volcanoes present. I always wondered, when the volcanoes move away from the hot spot, do they stop having magma right away? Can they still cause strong eruptions? Or eruptions at all? What’s the process exactly of becoming an inactive volcano?

These video are very informative and interesting.

To clarify, why Atlantic ocean has only spreading?Why not subduction happening?

-Abigail Doris

These two videos taught me a lot of interesting information. What I found really interesting was that 45 million years ago India collided with Asia and this collision is still going on today. This is causing the Himalayan Mountains to continue growing. I did not know that, and it made me think about how fast the Himalayan Mountains may be growing. Another question I had while watching the video on Plate Tectominc Global Impacts was what happens or what is present where the three ridge ocean centers meet in the Indian Ocean?

these videos shared some thoughtful knowledge about the place we are living in. However, if we are assuming that there were more than just one super-continent, why is Pangea the mainstream.

I found it very interesting when it talked about the formation of the Himalayas and the volcanic mountain ranges in California and other along the coastal boundaries of other plates, yet one of the largest mountains was left out. Denali, or Mount McKinley, has a bigger body than Everest, more elevation gain from base to peak. I was wondering what would’ve caused such a large mountain to form there? I suppose it would’ve been something similar to the Himalayas, where two continental plates collided, if so which plates? I thought it surely would’ve been mentioned in the video if it was notable enough but alas, here we are.

In the videos we learnt that there are four different layers of Oceanic Crust: Pillow Basalts, Sheeted Basalt Dikes, Gabbro, and Sediments. Are there layers that can be identified in continental crust? Which of them are the same? The only one I can think of is the Sediments layer.

What I found most interesting was water’s effect on the asthenosphere at a subduction zone. Because it reduces the melting point of the asthenosphere, it causes it to melt and the molten magma thereby becomes less dense and rises to the surface along with the water. The sheer amount of water at a subduction zone is what causes such explosive volcanoes to exist and my question is how much water is required to create such an explosion?

I found it super interesting to learn about pangea and how our continent’s placement came to be. My favorite part of the video when they showed the triple junction where three different seafloor spreading centers come together and showed actual pictures where you can see the new rift zone appearing. It was mentioned that about 45 million years ago India collided into asia in a continent continent collision and is continuing to do so, and that made me wonder if it would ever stop? Also in millions of years from now, will the placement of the continents be completely different from how we see them now?

I personally found the subject of supercontinents quite interesting because it seems that (like everything else on earth) it is a cycle. The last supercontinent to form was Pangaea and there were six supercontinents that  have formed and dismantled before Pangaea was formed. Considering there is knowledge of the speed at which the continents move and which directions, is there a computer simulation that depicts a prediction of when  the next supercontinent forms and how it could possibly look like?

Something that I found interesting from the second video was that there was that there is a diverging spreading center on both the Northwest coast and in the Gulf of California in Mexico. From the simulation they played on the video, it looked as if land was moving in from the South-Southeast to make the west coast of America longer.  I know that plates move very slowly, at speeds of millimetres per seconds, so it would take thousands of years before it would be a noticeable difference, but does this imply that in some thousands of years later the west coast would have moved a sizable distance even further to the west?

test reply

yes.