Plate Tectonics

Case study, Week 1, Assign#3, The Pu’u O’o eruption!!!!

Image Described in CaptionThe Pu’u O’o eruption on January 3rd, 1983 on the “Big Island” of Hawaii 

Image result for plate boundaries near hawaii

The islands of Hawaii have been and are still being created by a hot spot in the middle of the pacific plate. Some plate boundaries include Divergent boundaries (East pacific rise and the Chile rise) boundaries, Convergent boundaries (subduction under the North american plate, Okhotsk plate, Philippine plate, and Indo-Australian plate), and Transform boundaries along some of the North American plate.   

The specific type of event that happen on January 3rd was a Fissure eruption (volcanic hazard) where a lines of vents 6 kilometers (3.7 miles) wide gave way (often called a curtain of fire) along the eastern rift system of Kilauea.

Image result for east rift zone of kilauea Since then, lava flows have been produced from these fissures since 1983. changing paths over time.

The most interesting thing I have found out about this eruption is it is ranked as the longest and voluminous known outpouring of lava from Kilauea Volcano East rift zone in more than 500 year and its most dangerous period of time was in 1990 when a breakout flow from a lava tube slowly entered the town of Kalapana. After 9 months, the town was completely engulfed by 15-25 meters ( 50-80 feet) deep of lava. So cool!

Fire FountainsImage result for kalapana hawaii

 

A few sites that helped me understand the topic better:

http://www.geology.sdsu.edu/how_volcanoes_work/

https://www.geolsoc.org.uk/Plate-Tectonics/Chap3-Plate-Margins/Mid-plate/Hawaiian-Islands

https://volcanoes.usgs.gov/volcanoes/kilauea/geo_hist_1983.html

Strength of Tectonic Plates May Explain Shape of the Tibetan Plateau

 

The Tibetan Plateau covers the majority of Central Asia and Eastern Asia. I as so intrigued to read more about the Tibetan Plateau. The Tibetan Plateau has the highest peaks in world and stands 3 miles above sea level which is why it is coined for being the Roof of the World. The Himalayans mountains and the Tibetan plateau have formed because of the collision between the Indian Plate and the Eurasian Plate which began more than 50 million years ago and still continuous to change even today the plates move at rate about 4 to 5 cm a year  A plateau is created when areas of flat land is formed beneath the flat land lies vast amounts of molten rock. The collision of the Indian plate mostly made from oceanic crust was pulled beneath the Eurasian Plate that was being pushed up to form the mountains. The environment of the Tibetan Plateau features a alpine tundra or treeless highland area with low perception. Common wildlife in the Tibetan Plateau are snow leopard, grey wolves, yaks, cranes, water buffalo.

The Tibetan plateau environment is also known for its glaciers and lakes and main source of the water systems throughout Asia. Satluj of Indus river water system, Ghaghra and Gandak of Ganges river water system, Yellow River, Yangtze river these water systems are important for people but for the wild life as well. There is also a vast amount of rich mineral resources as well, gold, copper, lithium, lead, zinc, and Uranium.

Resources

https://www.sciencedaily.com/releases/2017/07/170724113557.htm

Tectonic Plates (Liz)

My chosen website: http://www.crystalinks.com/platetectonics.html

Three facts of information I learned from this website was the difference between a major and a minor tectonic plate, the names of the many plates, and the Greek meaning behind why we call them plate tectonics.

  • The difference between a major and miner plate basically has to do with size. Major plates are the largest plates and make up most of the earths surface where minor plates are small. As the article states, the minor plates are not less important than the major and the the lots more minor plates than major.
  • The 8 major plates according to the website are
    • Africa Plate
    • Antarctic Plate
    • Indo-Australian Plate
    • Australian Plate
    • Eurasian Plate
    • North American Plate
    • South American Plate
    • Pacific Plate

A list of a few minor plates are

 

    • Arabian Plate
    • Juan de Fuca Plate
    • Caribbean Plate
    • Cocos Plate
    • Nazca Plate
    • Philippine Sea Plate
    • Scotia Plate

 

  • The Greek meaning behind the term plate tectonics is “builder” or “mason” according to the website. I am not sure if this is correct, however. When I went searching around the internet to clarify this statement, no other website backed this statement up. Which brings me to the more important lesson learned about how websites need to be well reviewed and sourced.

All-in-all, this website made me want to export the typic more.

Unit 2 Assignment 1 – New Resource

I found a page that the National Oceanic and Atmospheric Administration made about plate tectonics, and I think it’s a good resource for anyone looking for a solid overview of  the different types of plate boundaries. In addition to the main page, the website has a great slideshow that discusses plate tectonics and the earth’s interior.  A lot of the information on the website is stuff I’m familiar with, but I did learn a few things:

  1. The Chile Triple Junction is the only triple junction where an active spreading ridge is subducting beneath a continent. I haven’t exactly studied the different types of triple junctions in the world, but it’s pretty interesting that this triple junction is unique.
  2. The second little factoid that I learned from this page was that there are more than 2,000 “strong quakes and large eruptions” happen each year. I don’t know exactly how the NOAA quantifies “strong” quakes or “large” eruptions, but darn if that isn’t a lot of them. I did some pretty advanced math and calculated that there are an average of five and a half strong quakes or large eruptions per day. I know Kenai had a pretty big earthquake a couple of days ago, but I really didn’t realize that there were so many larger events.
  3. Finally, I learned that “tectonics” comes from the Greek word for carpenter. “Tekton” means “craftsman”, or carpenter, and I think that’s pretty neat.

 

Life and Plate Tectonics

Since I have already taken a class on plate tectonics, I wanted to learn about something more “outside the box” when it comes to the motion of plates on earth.

https://cosmosmagazine.com/geoscience/plate-tectonics-the-hidden-key-to-life-on-earth

The cosmos magazine had a very interesting article about how plate tectonics relates to the existence of life on earth. I never thought of plate tectonics as being an ingredient to life until I came across this article. One thing I learned that I didn’t know before is that plate tectonics started on earth around 2.7 Billion years ago, and did not start initially when the planet came into existence. It is not agreed upon what caused this sudden introduction of plate tectonics, but it is thought that maybe the mantle had a increase in magma activity, or the crust weakened enough for it to split apart and moving.

What makes tectonics relate to life is it’s influence on the carbon cycle. Plate tectonics is a major factor in volcanism, and having a source of CO2 in the atmosphere is essential to moderating the climate on earth and allowing life to exist. Without tectonic activity, the earth might have been to hold to be sustainable to life as it is today.

The article also talks about how earth would be similar to mars without tectonic activity, which I also haven’t heard before, but I think that is a little bit too soon to tell that as a fact because recent studies from universities like UCLA show that Mars might be tectonically active just like earth. With increased interest in sending astronauts to mars, I am curious if in my lifetime more information about tectonics on Mars will be discovered, potentially challenging the ideas that the Cosmos Magazine brings up.

I realize that this article doesn’t really teach the reader about how plate tectonics work, but I felt it was relevant because it suggested that volcanoes caused by plate tectonics are not only a natural hazard, but also an essential variable to making Earth habitable.

Plate Tectonics and Natural Hazards

Subduction zone presentation

3 major natural hazards occur due to subduction zones; volcanoes, earthquakes and tsunamis.

Volcanoes form from subduction zones due to melting of lithosphere overlying the oceanic plate that is subducting. Melt rises to the surface forming volcanoes, usually occurs about 100 km below the Earth’s surface.

Earthquakes are caused by the subducting oceanic plate when it moves deeper and parts of the slab crack. This can occur at the surface of the subducting plate all the down to the furthest depth of the plate (up to 670km). Earthquakes at the surface are caused by extension and earthquakes within the subduction zone are generally caused by compression.

The thing about earthquakes in subduction zones is that they are near or within the ocean and can cause tsunamis depending on the magnitude of the earthquake. Tsunamis generated from an earthquake can effect areas all around the ocean of origin.

 

Plate Tectonics

We as a State are lucky and unlucky in the fact how close we live in the sub-duction zone.

What is a Subduction zone was my first question. I learned that is cause by plates from the Pacific plate and the North American plate. The Pacific plate slides under the The North American plate, this creates seismic activity. The second thing I learned was, when two of the plates get stuck and can’t move forward they build up energy over time.  There are in fact different places that can release energy, one is horizontal plating that is far enough that it keep the sea bed more clam.  The other is on the fault plating which does cause tsunamis.  The third thing i learned the earths quakes caused by plating can last months after the energy has been released.

if you find this interesting this link  may have little more info on this subject. (https-www-theverge-com-2018-1-23-16922914-alaska-earthquake-tsunami-pacific-north-america-plate-boundary)

respectfuly

clmiller15

Plate Tectonics

 

  1. Link to the page USGS page that I am using today https://pubs.usgs.gov/gip/dynamic/tectonics.html
  2. I learned some very interesting things from my reading in the USGS page I posted. I learned that I am more interested in these topics than I initially thought. What has peaked my interest has been that this learning will better my understanding and preparedness of these types of geological hazards. I look forward to learning more about the geohazards in my direct area of the Kenai Peninsula and Cook Inlet. Plate tectonics directly relate to volcanic activity. Growing up I heard so much about the ancient city of Pompeii being destroyed by the volcano of Mount Vesuvius.  I assumed that this was the most deadly and destructive eruption in history. In fact, Japan’s Unzen Volcano erupted in 1792 and killed 15,000 people. Unzen is located on the Island of Kyushu, near Nagasaki. Mount Pinatubo erupted in 1991 and caused significant weather related issues around the world. Although located in the Philippines, Huge amounts of sulfur dioxide filled the stratosphere. Combined with water vapor in the air, this created what most people call acid rain (sulfuric acid). The damage to crops and plant and animal life must have been devastating. This sulfuric acid also blocked sunlight. This caused a .5 degree Celsius drop in temperature worldwide. Major earthquakes under the sea bed cause tsunamis Think of a jet airliner, flying near the surface of the ocean. Passenger jets typically fly near 500 miles per hour. Now, imagine a giant wave traveling at the same speed. This seams crazy, right? This does actually happen with a tsunami and they can travel well over 10,000 miles. I live in an area that holds the record for the second most powerful earthquake ever recorded. I live near the salt water as well. There is a 200 foot bluff that protects the area I live in. I used to think I was absolutely safe from tsunamis. After reading this, it makes me wonder how far the water could actually reach, considering the power of the tsunami and local rivers that empty into the salt water. When I mention the word, ”Java”, what is the first thing that comes to mind? I think of coffee shops on the way to work. After reading this web page I found that in 1883 near the islands of Java in Indonesia, the Krakatau Volcano erupted and caused a massive tsunami. There were a series of large tsunamis that washed away 165 coastal villages, killed over 36,000 people and was felt as far away as the Arabian Peninsula. I have supplied a photo of one of the active volcanoes I can see on a daily basis. This is Mount Redoubt in South Central Alaska. Photo credit: Wikipedia
  3.  

    Summit crater, active lava dome, and steam plume of Redoubt volcano, May 8, 2009. View is toward the southeast.

Hazards of Plate Tectonics

With the recent earthquake and tsunami threat for Kodiak Island and the coast of Alaska, I found the NOAA US Tsunami Warning System website. Within the website, there is abundant information about the causes, characteristics, and detection of tsunamis, along with safety and current research.

  1. According to the Global Historical Tsunami Database, tsunamis that cause damage or deaths near their source occur approximately twice per year. Tsunamis that cause damage or deaths on distant shores (more than 1,000 kilometers, 620 miles, away) occur about twice per decade. The website has a list of recent tsunamis dating back to 1996. For 2017 only 4 were recorded, and in 2016, 7 tsunamis.
  2. There are two types of tsunamis, local or distant. The type depends on the location of the source and where it may strike land.
  3. There are weather-generated tsunamis! Similar to earthquake generated tsunamis, but they are caused by air pressure disturbances often associated with fast moving weather systems.

http://www.tsunami.gov/

Short video on safety:

http://www.nws.noaa.gov/om/Tsunami/outreach.shtml

FEMA- Seismic Hazards

https://www.fema.gov/media-library-data/20130726-1545-20490-8169/mhira_n4.txt

The site I used is from FEMA, which relates tectonic movements to the potential ramifications from an emergency response perspective.

Items Learned

Although more prevalent in certain areas, tectonic shifting can cause earthquakes in interior areas of the United States as well.

There is not one sort of wave caused by tectonic shifts. There are P waves, S waves and surface waves.

“P (primary) waves, also called compressional or longitudinal waves, propagate through the Earth at a speed of approximately 15,000 mph (39,000 km/h) and are the first waves to cause vibration.”

“S (secondary or shear) waves are slower and cause structures to vibrate from side to side. Particle motion is back and forth at right angles to the direction of wave travel (Figure 16-1). S waves are the most damaging waves because unreinforced buildings are more easily damaged by horizontal motion than by vertical motion.”

“Surface waves (Raleigh waves and Love waves) travel even slower than P and S waves, and propagate along the Earth’s surface rather than through the interior. Particle motion is orbital, similar to motion in water waves. Particle motion in Rayleigh waves is elliptical in the vertical plane containing the direction of propagation, and amplitude decreases exponentially with depth. Particle motion in Love waves is horizontal, transverse to the direction of propagation, with no vertical motion. They both produce surface ground shaking, but very little deep motion.”

The Richter scale is one way of measuring tectonic movement, and the MMI Felt intensity breaks the movement down relative to what is felt and seen.