How are earthquakes created?
'An earthquake is what happens when two blocks of the earth suddenly slip past one another. The surface where they slip is called the fault or fault plane. The location below the earth’s surface where the earthquake starts is called thehypocenter, and the location directly above it on the surface of the earth is called the epicenter.'
'The earth has four major layers: the inner core, outer core, mantle and crust. The crust and the top of the mantle make up a thin skin on the surface of our planet. But this skin is not all in one piece – it is made up of many pieces like a puzzle covering the surface of the earth. Not only that, but these puzzle pieces keep slowly moving around, sliding past one another and bumping into each other. We call these puzzle piecestectonic plates, and the edges of the plates are called the plate boundaries. The plate boundaries are made up of many faults, and most of the earthquakes around the world occur on these faults. Since the edges of the plates are rough, they get stuck while the rest of the plate keeps moving. Finally, when the plate has moved far enough, the edges unstick on one of the faults and there is an earthquake.'
Source: http://earthquake.usgs.gov/learn/kids/eqscience.php
This second paragraph is very useful information detailing how earthquakes are created. I could use lots of diagrams, pictures maybe even animations to demonstrate the edge of the plates colliding with each other. I actually really like this idea and already I feel like I can play around a lot with these ideas.
There is a really nice animation of demonstrating how earthquakes are caused here; this is good inspiration for me.
Source http://news.bbc.co.uk/1/hi/4126809.stm
In my own words defining the creation of an earthquake: An earthquake is caused when the tectonic plates under the earth collide with each other when they are shifting. The impact of the collision causes a tremor on the earths surface.
Another useful source of information:'Earthquakes are usually caused when rock underground suddenly breaks along a fault. This sudden release of energy causes the seismic waves that make the ground shake. When two blocks of rock or two plates are rubbing against each other, they stick a little. They don't just slide smoothly; the rocks catch on each other. The rocks are still pushing against each other, but not moving. After a while, the rocks break because of all the pressure that's built up. When the rocks break, the earthquake occurs. During the earthquake and afterward, the plates or blocks of rock start moving, and they continue to move until they get stuck again. The spot underground where the rock breaks is called the focus of the earthquake. The place right above the focus (on top of the ground) is called the epicenter of the earthquake.'
Source: http://www.geo.mtu.edu/UPSeis/why.html
A recent, famous earthquake
The brief states the products were making an educational source for A level students. I was thinking focusing on a a specific earthquake as there would be tonnes of information on it which would be easy to gather and fun to structure it out on to a website. I googled 'Most famous earthquakes' and found a website which listed these:
- 1556: Shaanxi, China
- 1976: Tangshan, China
- 2004: Indian Ocean Tsunami
- 1920: Haiyuan, China
- 1923: Kanto, Japan
- 1948: Turkmenistan
- 2008: Sichuan Province, China
- 2005: Kashmir, Pakistan
- 1908: Messina, Italy
- 1970: Chimbote, Peru
So I looked at the earthquake in 2008 in China.
This earthquake
'In June 2008, low-lying areas in one of the towns most devastated by the earthquake were flooded as a torrent of water was released from a dangerous lake formed by landslides, dislodging wrecked homes, cars and corpses.
The surge of floodwater into the town, Beichuan, was part of an effort by engineers and soldiers to drain Tangjiashan, one of more than 30 so-called quake lakes that were formed by landslides. For weeks, the dam of rock and mud holding back the rising waters of the Jian River there had threatened to burst and flood towns and cities downstream that are home to 1.3 million people.
Another smaller earthquake struck the region in August 2008, damaging 258,000 homes and killing at least 32 people.
Thousands of the initial quake's victims were children crushed in shoddily built schools, inciting protests by parents. Local police harassed the protestors and the government criticized them. At least one human rights advocate who championed their cause was arrested.'
source: http://topics.nytimes.com/topics/news/science/topics/earthquakes/sichuan_province_china/index.html
I have also found a really nice, easy to understand animation plus a pdf of images and labels of how earthquakes are formed on an article off the bbc. I will definitly use information from there as I know bbc is very reliable and the images are very accurate and nice to understand, perfect for an a level student to learn.
source: http://news.bbc.co.uk/1/hi/4126809.stm
How earthquakes are recorded
I think this is a very interesting subject to understand how earthquakes exactly are recorded, how does a rictor scale work?
Earthquakes are measured by an instrument called a seismometer which are also known as seismographs. These instruments measure the motions of the ground generated by earthquakes and explosions and any other type of seismic source. The recoding produced by these tools have allowed seismologists to map the interior of the earth.
'The Richter Scale measures the magnitude of the seismic waves or vibrations that travels across the earth's surface. The scale uses a logarithmic formula using high-frequency data collected from seismograph stations.'
'earthquakes are recorded by a whole network of seismographic stations located at strategic places across the world. A seismograph is a simple instrument that consists of a suspended weight with a pen attached to it. Next to the pen is a large paper roll.
Under normal conditions the pen draws a straight line. As the ground vibrates due to the tension released from below the surface of the earth, energy is released and travels outward in waves.
When the frame vibrates, the pen draws a zigzag pattern. This line is called a seismogram and records the amplitude of the seismic waves at the site.
The ground motion at each seismograph is recorded electronically at the recording site. As the wave expands from the earthquake, it reaches more distant seismic stations. Each station measures and times the distance and time the wave front passes the station and this is then tabulated until the epicentre is located.
With new technology, it became apparent that the Richter Scale was valid only for certain energy frequency and distance ranges. So scientists have developed new magnitude scales that are an extension of Richter's original idea.
These include body-wave magnitude, surface-wave magnitude, and moment magnitude. For very large earthquakes, moment magnitude gives the most reliable estimate of earthquake size.
Sometimes the magnitude is reported by different networks based on only their recordings. This difference is a result of the different instruments used and their locations with respect to the earthquake epicentre.'
source: http://www.pitara.com/discover/5wh/online.asp?story=121
I have also found a really nice, easy to understand animation plus a pdf of images and labels of how earthquakes are formed on an article off the bbc. I will definitly use information from there as I know bbc is very reliable and the images are very accurate and nice to understand, perfect for an a level student to learn.
source: http://news.bbc.co.uk/1/hi/4126809.stm
How earthquakes are recorded
I think this is a very interesting subject to understand how earthquakes exactly are recorded, how does a rictor scale work?
Earthquakes are measured by an instrument called a seismometer which are also known as seismographs. These instruments measure the motions of the ground generated by earthquakes and explosions and any other type of seismic source. The recoding produced by these tools have allowed seismologists to map the interior of the earth.
'The Richter Scale measures the magnitude of the seismic waves or vibrations that travels across the earth's surface. The scale uses a logarithmic formula using high-frequency data collected from seismograph stations.'
'earthquakes are recorded by a whole network of seismographic stations located at strategic places across the world. A seismograph is a simple instrument that consists of a suspended weight with a pen attached to it. Next to the pen is a large paper roll.
Under normal conditions the pen draws a straight line. As the ground vibrates due to the tension released from below the surface of the earth, energy is released and travels outward in waves.
When the frame vibrates, the pen draws a zigzag pattern. This line is called a seismogram and records the amplitude of the seismic waves at the site.
The ground motion at each seismograph is recorded electronically at the recording site. As the wave expands from the earthquake, it reaches more distant seismic stations. Each station measures and times the distance and time the wave front passes the station and this is then tabulated until the epicentre is located.
With new technology, it became apparent that the Richter Scale was valid only for certain energy frequency and distance ranges. So scientists have developed new magnitude scales that are an extension of Richter's original idea.
These include body-wave magnitude, surface-wave magnitude, and moment magnitude. For very large earthquakes, moment magnitude gives the most reliable estimate of earthquake size.
Sometimes the magnitude is reported by different networks based on only their recordings. This difference is a result of the different instruments used and their locations with respect to the earthquake epicentre.'
source: http://www.pitara.com/discover/5wh/online.asp?story=121
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