The How And Why Of Earthquakes

Discussion in 'Science & Nature' started by Babs Hunt, Apr 19, 2016.

  1. Babs Hunt

    Babs Hunt Veteran Member
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    http://easyscienceforkids.com/all-about-earthquakes/
    Earthquakes and Why They Happen
    [​IMG]

    The ground shakes, buildings tumble and the earth heaves and cracks. Serious earthquakes are terrifying and dangerous, but are rare in the U.S. But why do earthquakes happen? The earth is made up of four layers – the inner core, outer core, mantle and crust. The mantle and crust are a thin skin compared to the other layers. The mantle is about 1,750 miles thick, while the crust is only about 8 miles thick. This thin skin is broken into pieces called tectonic plates. The plates are like puzzle pieces, floating on top of the Earth’s inner core. Sometimes the pieces slide under or against each other and become stuck.

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    Fun Facts for Kids on Earthquakes – Image of a Road Damaged by Earthquake

    When the pieces slide apart, they create tremendous force. This force causes the earth to shake and ripple. Over 80 percent of the earth’s earthquakes happen in the Pacific Ocean, in a place known as the “Ring of Fire.” Annually, around 10,000 people die in earthquakes every year. Most of the deaths happen when people are trapped in falling buildings. After an earthquake, mudslides, fires and tsunamis can also hurt people.

    Yes, that link does say easy science for kids. Since earthquakes are happening frequently again these past few days and we now have a Science and Nature section of the Forum...I wanted to start a tread about earthquakes. I don't know much in the area of Science and I don't know much about earthquakes either so I wanted to find a website that would use simple language to tell me about them. Plus I hope some of you will be able to share some interesting things you know about earthquakes too.

    So just think of the link above for all of us Big Kids!

    My first question is: Has anybody on this Forum ever experienced an earthquake?

    I first became interested in earthquakes when I saw the movie Earthquake with Charleston Heston and Ava Gardner. But even back then it was more the movie about earthquakes that drew my interest...and not the scientific explanations of the how and why of them. In school Science was not one of my favorite subjects either so even though I probably did learn some things about earthquakes during my school years...it just never stuck with me. I never felt the need to know the how and why of some things.I just knew if something happened, then it was real...and that's all that really mattered to me when it came to earthquakes. As I've gotten older though I find I am much more curious about the how and why of things. And the more often things like earthquakes happen...the more my mind wonders how and why too.

    I've seen a lot of earthquake movies since my first one...and since Scientists, etc. know so much about them now the movies have become ever more realistic of what earthquakes and humans going through them are really like. All of this makes me more interested in this part of Science today.

     
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  2. Kate Ellery

    Kate Ellery Veteran Member
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    Yes ,it was only a small one by comparison to the ones ,we have seen on TV in Last few days
    We live in South Australia ,we go up to Queensland for a month during winter ..July-- Aug to escape a little of SA's cold days/ nights..
    We had just arrived at our rented unit ,last August ,( at lunch Time ) we decided we would have a cup of coffee before venturing out to do a little shopping when the large fridge came out from and banged back into the wall behind it ,pictures on the wall started shaking and banging on the walls ...We both looked at one another ..wide eyed ..oh dear a earth tremor ..so we thought ..but in the next day's press it had headlines Gold Coast experiences 5.7 earth quake
    I hope if they have any more they get it over and done with before we arrive there this year ..it's a real scary feeling
    I believe its very rare for that part of Aust to experience earth quakes ,However where we live in SA is right on a major fault line,for earth quakes :eek:

    Quote from added link ............Saturday's quake was the biggest to hit the state since 1918, and 10 to 15 times stronger than the magnitude-5.3 quake that struck south-east Queensland on Thursday.
    "
    http://www.abc.net.au/news/2015-08-...wo-days-felt-in-south-east-queensland/6665546
     
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  3. Babs Hunt

    Babs Hunt Veteran Member
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    I bet that was scary Kate. I know there is the San Andreas fault line in California which I believe is a major fault line here in America but I did not know Australia had a major fault line too. That's very interesting that you live on that major fault line over there...and just a little anxiety inducing too. :) Do you have many tall buildings where you live?
     
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  4. Kate Ellery

    Kate Ellery Veteran Member
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    Only two story buildings where I actually live in a country town ..I will do s bit more reasearch on Adelaide . and post tomorrow ..but I know our almost complete $$$$$ hospital is alleged to be built right on a major fault line ..and allot of talk about the use of cheap,steel in the new structure ...from O/S when we have a major steel producer in this state ...talk latter hubbies birthday today on way out for lunch :D
     
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  5. Babs Hunt

    Babs Hunt Veteran Member
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    This map shows all the areas where earthquakes can occur in America and what states have the highest hazard of experiencing earthquakes. As you can see all of the West Coast States are in the highest hazard category earthquake probability.

    In 1663 the European settlers experienced their first earthquake in America.

    US-FAULT-LINES.jpg
     
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  6. Babs Hunt

    Babs Hunt Veteran Member
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    world-fault-line-map.png

    Here is a map of known World wide Epicenters or fault lines.

    The earliest recorded evidence of an earthquake has been traced back to 1831 BC in the Shandong province of China, but there is a fairly complete record starting in 780 BC during the Zhou Dynasty in China.
    It was recognized as early as 350 BC by the Greek scientist Aristotle that soft ground shakes more than hard rock in an earthquake.
     
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  7. Babs Hunt

    Babs Hunt Veteran Member
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    Just like with everything else in Creation there are myths and legends about how things came into being. Here are some interesting earthquake myths from around the World.

    Ancient Myths


    Greece

    Thales of Miletos (6th century BC) believed an agitation of the great sea, on which the earth floats, produced earthquakes.



    Mexican Vaqueros, California

    El Diablo, an Indian god, made a giant rip in the ground so that he and his cohorts did not have to take the long way around when they wanted to stir up mischief on Earth.



    Gabrielino Indians, Southern California

    Long ago, Great Spirit made a beautiful land that turtles carried on their backs in lakes and rivers. One day the turtles began to argue. Three swam east; the other three swam west. The earth shook and cracked. The turtles could not swim far, because their load was heavy. So they made up. But once in a while, the turtles argue again. Each time, the earth shakes.



    Hindus of India

    They believed that eight mighty elephants held up the land. When one of them grew weary, it lowered and shook its head, causing an earthquake.



    Kamchatka, Siberia, Russia

    A god named Tuli drove an earth-laden sled pulled by dogs. When the dogs stopped to scratch at fleas, the earth shook.



    Mongolia, China

    A gigantic frog which carried the world on its back twitched periodically, producing slight quakes.



    Peru

    Whenever a god visited the earth to count how many people were there, his footsteps caused earthquakes. To shorten his task, the people ran out of their houses to shout 'I'm here, I'm here!' (incorporating in their myth, the wisdom of leaving flimsy houses during an earthquake).



    Japan

    A giant catfish lived in mud beneath the earth. A prankster, it could be restrained only by Kashima, a god who protected the people from earthquakes. So long as Kashima kept a mighty magical rock over the catfish, the earth was still. But when he relaxed, the catfish thrashed about, causing earthquakes.
     
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  8. Yvonne Smith

    Yvonne Smith Very Well-Known Member
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    One of the youtube channels that I subscribe to is called "Dutchsinse", and he is a person from the St. Louis area who follows very closely all of the earthquake activity in the world, and posts videos about what is happening, as well as what he thinks might happen next.
    He also looks at where fracking is taking place, since that is now causing earthquakes in places that are not usually considered to be dangerous for earthquakes.
    Volcanoes are also affected by the earthquakes, and vice-versa; so monitoring volcanic activity is an interesting and connected subject.
    Here is the latest youtube video from Dutchsinse, and I believe that he also has a facebook page and an earthquake group, although I don't follow that one.

     
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  9. Babs Hunt

    Babs Hunt Veteran Member
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    The Bible talks about earthquakes. These Scriptures about earthquakes are from the King James Version of the Bible.

    So being a Christian who believes the Bible has also peeked my interest in earthquakes because the ever increasing frequency of them to Christians is a sign that Christ will be returning to earth to set up His eternal Kingdom. According to the Book of Revelation right before Jesus Christ returns the biggest earthquake of all time will happen.


    Luke 21:11 - And great earthquakes shall be in divers places, and famines, and pestilences; and fearful sights and great signs shall there be from heaven.

    Mark 13:8 - For nation shall rise against nation, and kingdom against kingdom: and there shall be earthquakes in divers places, and there shall be famines and troubles: these [are] the beginnings of sorrows.

    Revelation 11:13 - And the same hour was there a great earthquake, and the tenth part of the city fell, and in the earthquake were slain of men seven thousand: and the remnant were affrighted, and gave glory to the God of heaven.

    Matthew 24:7 - For nation shall rise against nation, and kingdom against kingdom: and there shall be famines, and pestilences, and earthquakes, in divers places.

    Acts 16:26 - And suddenly there was a great earthquake, so that the foundations of the prison were shaken: and immediately all the doors were opened, and every one's bands were loosed.

    Revelation 6:12-14 - And I beheld when he had opened the sixth seal, and, lo, there was a great earthquake; and the sun became black as sackcloth of hair, and the moon became as blood;...

    Revelation 16:18 - And there were voices, and thunders, and lightnings; and there was a great earthquake, such as was not since men were upon the earth, so mighty an earthquake, [and] so great.

    Matthew 28:2 - And, behold, there was a great earthquake: for the angel of the Lord descended from heaven, and came and rolled back the stone from the door, and sat upon it.

    Isaiah 24:19 - The earth is utterly broken down, the earth is clean dissolved, the earth is moved exceedingly.

    Ezekiel 38:19 - For in my jealousy [and] in the fire of my wrath have I spoken, Surely in that day there shall be a great shaking in the land of Israel;
     
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  10. Babs Hunt

    Babs Hunt Veteran Member
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    Here's a video of the earthquake and resulting tsunami in Japan in 2011. This is the earthquake I remember most of all as probably a lot of you do too.

     
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  11. Kate Ellery

    Kate Ellery Veteran Member
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  12. Babs Hunt

    Babs Hunt Veteran Member
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    Thanks Kate. Do you really think your almost new hospital is not following earthquake code in their building materials. I guess I should even ask if there is a certain code those materials have to adhere to when the building is erected in an "earthquake zone"... I know they have those kind of codes here in America, but not sure if it is that way in other areas.
     
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  13. Babs Hunt

    Babs Hunt Veteran Member
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    By the way @Kate Ellery Love your avatar, my "baby" sister love Minnie and Mickey, has her guest room decorated in a theme of them and spends all her vacation time "visiting" with them in Orlando, Florida. :) She and her husband plan to "retire" and get jobs at Disney World just so they can live their dream...or would that be "theme?" :D
     
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  14. Kate Ellery

    Kate Ellery Veteran Member
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    Here is a link for the buildings up the Gold Coast ,@Babs Hunt where we experienced the earth quake on August 1 st last year.....https://en.m.wikipedia.org/wiki/List_of_tallest_buildings_on_the_Gold_Coast.
    Link is for suffers paradise ....known as the Gold Coast ...
    I believe the Earth Quake we experienced was felt mostly where we were at the time ..they had a few tremors prior to us going up there ,last year ..but we thought nothing of it until the" big " one struck the day we arrived (Saturday 1st Aug)

    We go up there ,every winter for 4 weeks ...the part of the Gold C where we stay is called Coolangatta, it's on the the New South Wales/ Queensland border....it's approx 20 km south of Surfers P ....it's a much slower pace . For oldies ....(The Winter) daytime temps up there are in mid 20's C ..compared to South Aust daytime winter temps ..10-12 C ..We are just going into winter ..so we will be looking forward to escaping again this year
     
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  15. Kate Ellery

    Kate Ellery Veteran Member
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    I'm a big "kid" @Babs Hunt I have a Micky and Minnie in my sewing room ..Hubby and I enjoy ballroom dancing and my avatar is M&M dancing :D:D
     
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  16. Martin Alonzo

    Martin Alonzo Very Well-Known Member
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    I have personal experience with earthquakes. Living on the north coast of the Dominican Republic there was one 10 years ago which hit Puerto Plata with 6.4 and it was strong enough to crake the walls of my home and we live 35 miles away. We have had a few small ones that we felt. The one that hit in Port-au-Prince in Haiti we felt it here which is over one hundred miles away. We are on the Caribbean plate which is always acting up just north of Puerto Rico where they have two or more earthquakes per day.
     
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  17. Babs Hunt

    Babs Hunt Veteran Member
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    Are there special preparations to take for earthquakes @Martin Alonzo? And do you live with any stress from knowing they can happen basically anytime?
     
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  18. Martin Alonzo

    Martin Alonzo Very Well-Known Member
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    We just accept and don’t worry I told my wife that 95% of the time the first is the strongest and if you survive it don’t worry. I had a few laughs that some of the people here after an earthquake they will not go back in their house for a few days out of fear. When we built our house it had extra rebar and I put in vertical bars as well which they do not normally do.
     
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  19. Yvonne Smith

    Yvonne Smith Very Well-Known Member
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    One of the worst earthquakes in the history of the United States was the New Madrid quake, which happened in the early part of the 1800's (don't remember the exact date offhand) . It caused repercussions all the way from the Great lakes to the Gulf of Mexico, and even the rivers ran backwards for a short time.
    Back then, very few people lived in that part of the country; but they have been saying for a while now that we are overdue for another large quake on that fault-line.
    If that does happen, and it is as severe as the last ones were, then a good share of the eastern part of the country will be affected directly, and travel from east to west could be completely cut off, should that happen.

    Of course, the other big one to worry about, would be the Yellowstone Caldera, and if that erupts due to a large quake at the new madrid fault, then most of the US will be covered in ash, some of it very deep, like a bad blizzard would do.
    I just listened to this video that is about a FEMA meeting that just took place after the earthquakes in Ecuador and Japan, and if what this man is saying is even close to true, then we all need to be getting prepared.
    He shows a map at the end where he says they are sending the FEMA troops, and the parameters look like it could involve either New Madrid, or Yellowstone, or both.
    Just an afterthrought........ This would definitely put the whole country under martial law, no elections period.

     
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  20. Yvonne Smith

    Yvonne Smith Very Well-Known Member
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    We mainly heard about the three large earthquakes in Japan recently; but there were actually over 600 earthquakes in a week's time. It was what is called an earthquake swarm, and they are apparently still concerned about the nuclear plants there.
    The quakes have also affected the volcanos, and Mt. Aso is erupting now, as well.
    It seems like earthquakes and volcanos are always directly related.
    In Washington state, they were working on the bridges near both Mt.Rainier and Mt. St. Helens because they were concerned about earthquakes collapsing the bridges and cutting off travel into the areas.

    https://www.rt.com/news/339788-japan-volcano-eruption-quakes/
     
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  21. Chris Ladewig

    Chris Ladewig Well-Known Member
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    I lived in California during the 71 and the 93 or 94 not sure which year the second one was, but I can tell you they are frightening. They leave you feeling totally helpless. You can't stand and walk you have to crawl. Things are flying out of cabinets and off shelves and walls. Furniture tips over, broken glass is everywhere. Certainly wouldn't want to do it again.
     
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  22. Frank Sanoica

    Frank Sanoica Very Well-Known Member
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    Here are a few images, Feb. 1971. Quoted excerpts. "The 1971 San Fernando earthquake (also known as the Sylmar earthquake) occurred in the early morning of February 9 in the foothills of the San Gabriel Mountains in southern California."
    "The event affected a number of health care facilities in Sylmar, San Fernando, and other densely populated areas north of central Los Angeles."
    From: https://en.wikipedia.org/wiki/1971_San_Fernando_earthquake

    My Aunt and Uncle lived then in Sylmar, over ten years. As chance would have it, they were in Las Vegas the day the quake occurred, and upon returning home to Sylmar, found their chimney had collapsed, and a large, very heavy glass mirror which had been hanging on the wall above the headboard of their bed, had crashed down on top of it, shattering on the headboard. My Uncle thought they might have been seriously injured, had they been home in bed. So it goes...... Frank


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    Collapse of four buildings at the Veterans Hospital complex

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    Interstate 210 / Interstate 5 overpass collapsed onto San Fernando Road

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    Damage to the Lower Van Norman Dam
     
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  23. K E Gordon

    K E Gordon Very Well-Known Member
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    Yes, the 2011 quake wsa centered is the county where I live. I was not home at the time, but at a Starbucks several miles away. There was lots of damage in this county, but a lot of it was to structures and not necessarily visible to the naked eye. What was really scary was the after shocks as some were quite intense. One happened while we were in bed, and was seriously concerning. I don't envy anyone living in an earthquake prone zone.
     
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  24. Yvonne Smith

    Yvonne Smith Very Well-Known Member
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    More earthquakes near Yellowstone Park, where the caldera is at that will be so bad if it erupts ! !
    My son in Idaho posted on Facebook that they felt an earthquake last night, so I went to the earthquake page to look and see exactly where and how strong it was.
    It turned out that the quake was in Lincoln, Montana, and was about 5.8-5.9. There was about 5-6 quakes, most of them just a little weaker; so a small swarm of quakes there.
    Lincoln is just northwest of Yellowstone Park, and close enough for this to become worrisome. Here is the alert from Dutchsinse about the quake.

     
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  25. Cody Fousnaugh

    Cody Fousnaugh Very Well-Known Member
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    Lots of folks, living in states outside of California, are always teasing people that live there about earthquakes. Whereas, earthquakes have been reported in other states, like Montana.

    I had never experience one until I was in the Navy, staying at the Armed Forces YMCA in San Diego. I was woken up on either a Saturday or Sunday morning with my bed shaking fairly bad. The shake was pretty short, but it sure got me out of my bed. I actually thought someone/something was under my bed. Later I found out it was a earthquake.

    Was in another one when living in Anaheim, California, staying at a motel. It was in the morning, I was up and the room started to shake. I knew what was happening and walked fast out the door and onto the walkway. My room was upstairs. I looked out and could see some electrical transformers sparking on the street next to the motel. Quake didn't last long and no major damage, that I heard about.

    Another time, I was in the restroom (on the toilet) at work. The room started to shake and I knew what it was. Came out of the restroom (fully dressed) to some co-workers laughing.

    Since moving from California, haven't experienced another earthquake.
     
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