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Earthquakes 101

Apr 28, 2015

Thousands of earthquakes happen across the US each year. The good thing is, almost all of them are too small to feel. Most earthquakes in North America happen west of the Rocky Mountains, but there are still 39 states that are at serious risk for quakes.

Plate Tectonics

Our planet is divided into a three main layers: a solid core, a liquid magma mantle and a crust , which floats on top. That top crust is made up of individual plates, which are kept in constant motion by convection currents in the magma.

Tectonic PlatesTectonic Plates

Types of Plate Boundaries

Earthquakes mostly occur at the boundary where one plates meets another. Plates either converge, collide, diverge or move past each other when they meet. When plates "converge," it means that one plate is slowly pushed beneath the other over the span of several thousand years. Plates that collide push rock layers upward, which creates mountains. When plates move away from each other or "diverge," lava comes up from the mantle and cools to form new sections of crust. Other plates simply move slowly past each other.

Earthquake!

In some places, the plates become locked together. Energy builds up in the locked plates, which is released in the form of an earthquake when the plates finally give. The place where the earthquake originates beneath the surface is called the hypocenter. The point on the surface directly above the hypocenter is called the epicenter - a word you've probably heard many times in the news whenever a major earthquake is reported.

Ride the Waves

An earthquake emits its power as three waves of energy. Primary waves (a.k.a. P-Waves) are felts as a sudden jolt. Secondary waves (a.k.a. S-waves) arrive moments later and are felt as a more ongoing side-to-side shaking. Surface waves arrive after the main P and S waves, and radiate outwards from the epicenter.

Earthquake WavesEarthquake Waves

Recording Zigzags

A seismograph is a machine that records the ground vibrations during a quake. A needle keeps drawing straight lines until the earth trembles, then the lines start to zigzag. The bigger the zigzags, the bigger the quake. The strength of an earthquake is measured by the Richter scale. Based on the seismograph readings, the Richter scale rates a quake using numbers 0-9, nine being the mother of all quakes.

Home-Made SeismographHome-Made Seismograph

Earthquakes: The Richter Scale

  • 1: Generally not felt, except by instruments.
  • 2: Generally not felt, except by instruments.
  • 3: Sometimes felt by people, but no damage.
  • 4: Sometimes felt by people, but no damage.
  • 5: Felt by most people, damage near epicenter (where the plates actually smashed into one another).
  • 6: Damage to buildings within six miles (10 km) of the epicenter.
  • 7: Serious damage to buildings within 60 miles (100 km) of the epicenter. Loss of life.
  • 8: Major earthquake with damage being caused to a huge area. Loss of life over 120 miles (200 km).
  • 9: Very rare. Major damage and loss of life up to 600 miles (1,000 km) away.

The Richter ScaleThe Richter Scale

Are They Predictable?

So far, scientists have yet to develop a reliable way of predicting earthquakes. There are, of course, many factors that they believe lead up to earthquakes, like change in groundwater chemistry, foreshocks (small, insignificant quakes) and strain in underground rocks. Because each quake seems to be caused by a different combination of these factors, it makes it very difficult to make predictions far enough in advance to help people. Seconds before a quake, pets like dogs and cats might get a little freaky, as they seem to be able to feel the trembling well before we do.!

What To Do In An Earthquake

One of the biggest quake dangers is being hit on the head or trapped under something. If you are indoors, stay put. Place something protective on your head and crouch under a table or stand in a doorway. If you are outside, quickly find an open space and stay away from things that will fall on you. After an earthquake, be prepared for aftershocks. Aftershocks follow earthquakes and are usually smaller than the actual quake. They are dangerous because they can cause things that were weakened from the original earthquake to fall down.

Earthquake Preparedness KitEarthquake Preparedness Kit

For more information on earthquakes check out check out www.fema.com.

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Disaster You'd Least Like to Get Caught In?

  • Hurricane.
  • Flash flood.
  • Avalanche.
  • Earthquake.

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rainbowpoptart
rainbowpoptart posted in General:
This is probably the cutest thing about growing up I've ever read, I just... Everyone grows up. No one's the exact same person they were 3 years ago, sometimes they're not even the same way they were 3 days ago. Every single is person is going to look back at their past self and cringe at something- something they said, something they did, something they didn't do. It's a sign of maturity. Everyone gets there (eventually; some earlier than others). I came back from a break around two or three months ago and wow did I feel embarrassed. I was in such an extreme scene phase when I made this account and everything was so.. yikes. My bio and albums were scattered with pictures of band members and "emo" YouTubers and I wanted to, like, burn it all (I deleted a lot of them, but the less cringey ones are still there). And my username..? Oh man my username. Not gonna be able to live this one down, that's for sure. I'm going to stay until I'm 18, if I find the time to (which I should because cyber school isn't that time consuming so). Maybe the remnants of 12 year old Kristin are the bane of my existence, but I've made some nice memories here, and I'm looking forward to making many more. (:
reply 14 minutes
AlphaT
AlphaT posted in Debating:
@Boysrock50  Do you mind if my response is lengthy?
reply 19 minutes
Boysrock50
Boysrock50 posted in Debating:
"AlphaT" wrote:   1. He's building a wall to keep illegal immigrants out. Illegal immigrants are people who come into the United States without following our immigration laws. In other words, he's building a wall so that people will stop breaking the law.  2. He's hired many Muslims and has many Muslim friends. His ban on Muslims has recently changed, but even in its' original state, it was a temporary ban meant to combat radical Islam. Trump's Muslim policies have never had anything to do with thinking that all Muslims are bad, it's just that most terrorists are Muslim and a temporary Muslim ban would eliminate most of the terrorists coming into our country.  3. Business deals with politics, and perhaps we need someone who's not a politician? Many have become corrupt, have been found to blatantly lie to their people, have not kept their promises after being elected. If anything, the fact that Trump is successful and yet not a politician is even more of a reason to vote for him.  Honestly, I thought the whole "Trump hates Mexicans and Muslims" thing would have been over by now. It's so obvious that he doesn't hate them, all you have to do is listen to what he says.    1) Just a few issues with the wall, disregarding the purpose. Is the wall going to replace current fencing? There may be major breaches whilst the wall is under construction. Will Trump have permission to build on every inch of land the wall is to be placed upon? How do you expect Mexico to pay for it when they outright refused? The geography alone will not make it easy to build completely along the border. Do you not think the alienating Mexico will create a larger social divide between the two countries? Finally, the engineering alone behind the wall is so implausible, I don't think Trump himself realises just how difficult it will be. 2) "He has many Muslim friends" - Oh dear, the classic anti-racist comment. 'I'm not racist because I'm friends with blacks'. His current proposal is just as absurd as his original proposal. He wants to ban Muslims coming from countries with a terrorist past? (or has he changed his proposal yet again?). Let's see, that consists of almost every country in the world if you want to go back far enough. How far in the past does he want to look? He also mentioned that he wants to suspend immigration of the same people trying to enter countries with US alliance. What, does he plan on flying over and stopping Iraqis from entering the UK? That should be entertaining. This ban though... yes, you're preventing 'Muslim terrorists' from entering the US but you're also preventing 1.5 billion other Muslims from entering. That totally seems fair. Why don't you ban holiday makers from entering the US too, because 1 decided to commit murder in the past? You'll probably get a similar attacker-innocent ratio. 3) Can we stop with the whole idea that being able to run a business means you can run a country? If that were true the UK would have had Sir Alan Sugar in power years ago. He's not even an economist. He probably doesn't even know what a Current Account is. The government isn't a business. The US has a free market economy, not a command economy. Trump isn't going to be a salesman, he's going to be a Prime Minister. It's vital he knows his politics. He may have ideas that people love but he has no idea how to run a country. P.s. I really worry for America's future economy if their idea of a 'successful' businessman is someone who ends up piling on so much debt that his businesses reach bankruptcy. There are countless businessmen more successful than Trump that 90% of people haven't ever heard of. Trump loves to big himself up and so do his supporters. You're making the man sound far greater than he actually is and it's possibly going to cost you the future of your country.
reply about 1 hour
AlphaT
AlphaT posted in Debating:
"KingShawn13" wrote:And now I ask how much of this was the fault of the Presidents before him and how much was actually his fault? It was entirely his fault, or the fault of his administration. The only thing you could blame Bush for is the war in Iraq, but even though Obama didn't start the war in Iraq, he ended it in the worst way possible. 
reply about 1 hour
trinityac
trinityac posted in General:
Don't worry I felt the same way when getting back on this account. I had made it when I was about to turn 11. I am 15 now. Time changes a lot and I am definitely not the same person I was when starting kidzworld. I'm starting my Sophomore year after summer is over and honestly I'll probably try to stick to this website for as long as I can until they lock my account when I'm 18.  
reply about 2 hours