Earthquakes occur many times everyday. Some are so small that they cannot be felt, but some are devastating.

Earthquakes are abrupt shakings of the ground. When there is a tremor, there are seismic waves and vibrations. Earthquakes are sudden movements along a fault line. The area where the plates shift is called the focus. Seismic waves move away from the focus of the quake. This is how temblors can cover a large amount of land. Tremors are caused by the releasing of stress in plates. When sudden energy releases from the Earth, there is usually an earthquake. The shaking of Earth’s crust is what a tremor is.

Temblors can cause many disasters, but they can cause good things too. If there were no quakes, the land would be flat and marshy. Quakes can affect businesses to fail and buildings to fall. Streets and bridges can collapse. Cars may crash and can result in fatalities. Power lines may break, this will cause no electricity. Tremors can also cause property damage. They can knock down trees, and even do damage to your house. Oil pipes may break and leak which may result in pollution and fires. Sometimes water pipes can explode and houses can lose their source of water. When water leaks, it can mix with mud and can generate a mudslide or landslide! Land and mudslides can also be generated by the large amount of shaking of the Earth which can cause chunks of land to slip. From the undulation underground, trees and levees can fall and dams can break which can create floods. Quakes can cause many bad things, but remember that they can help us too.

A major way that an earthquake can occur is the movement of plates. Another place a tremor can start is at a divergent boundary, when two plates move away from each other. The convergent boundary, which is where plates collide, can also generate a quake. The subduction of plates can cause a tremor by slipping under or over each other and not being in its regular position. Sometimes when the government tests weapons underground, there can be underground explosions. These explosions can cause a quake because it shakes the ground and causes plates to shift a little. One way a tremor is caused is by collapsing structures or buildings. Meteor impacts can cause earthquakes as well. Some quakes are generated by volcanic activity. There are many ways that earthquakes can be caused, and it is good to know about all of them.

Earthquakes are found near one of the ten plate boundaries, where two plates meet. Tectonic plates scrape and move past each other causing a quake. Another area where quakes are found is near faults. Faults are cracks in the Earth, at the meeting of plates. Tremors are found where plates slip from stress. Quakes are also found where plates build up pressure and then release all of it at once. Places where temblors are found are where plates scrape, collide, subduct, or move apart. A very common place where an earthquake can be found is in the Pacific Ocean. This is because many plates meet there. This area is called the Ring of Fire. Some areas are more in danger than others in having a quake, and this has done a lot to the land and sometimes has influenced where people live.

There are many ways that earthquakes can be measured. The Richter Scale is used to measure quakes. It measures the magnitude of a temblor on a scale from 1 to 10. It is one of the most commonly used scales. The Mercalli Scale measures the damage and the amount of fatalities there are during one quake. It is measured on a scale of Roman Numerals from I to XII (1 to 12). A seismograph measures the entire distance of a tremor. Seismic movement is the total amount of energy that causes the ground to move. There is a machine that is called the Magnemeter. It measures how much the ground moves from the quake. The Gravimeter measures the force of gravity on the land either pushed up, or pushed down. A Strain meter measures the strain in the rocks from the tremor. An interesting machine that is used is called the Tilt meter. It measures the water movement from an underwater quake. Scientists have many machines that can help us learn about earthquakes, but they are coming up with many more amazing inventions.

There are many types of seismic waves that all do different things. There are two main categories of waves which have more kinds within them. The two categories are Body and Surface waves. Body waves travel faster than Surface waves. The two kinds of Body waves are primary and secondary. The two types of Surface waves are rayleigh and love waves. Surface waves travel on the outer crust of the Earth. They do the most damage. Rayleigh waves move slower than love waves. Primary waves are the first to be felt, and they are in the category of Body waves. They move in a push-pull motion. Secondary waves roughly push the rock sideways, they are also Body waves. Seismic waves are very good to know about because they are very important parts of an earthquake.

There have been many terrible earthquakes in history. It has changed areas of the world a lot. A recent quake that happened in 2005 covered the areas of Pakistan, India, and Afghanistan. It caused approximately 79,000 deaths and had the magnitude of 7.4. Another tremor from last year was a 5.7 magnitude in Beijing, China. A different quake generated in the Indian Ocean, and measured 9.3 on the Richter scale. It caused a very large tsunami. About 140,000 Japanese citizens were killed in 1903 in Tokyo, Japan by an 8.1 temblor. Kashmir had a terrible earthquake that killed around 40,000 people and measured 7.6 on the Richter scale. In the town of Leninakan, Armenia in 1988, a temblor caused about 25,000 deaths. A quake which caused many deaths was in Tangshan, China in 1976. Approximately 650,000 were killed. Anchorage, Alaska had a 9.5 tremor in 1964 that caused many deaths. In Chile in 1960 there was a tragic earthquake that was 9.5 in magnitude. The tremor created tsunamis, volcanic activity and landslides. Many people were killed. These were some terrible temblors in history.

It is very important to be prepared and stay safe during an earthquake. If you are outside during a quake, go to an open area so that telephone poles and trees can’t fall and hit you. If you are inside, you should stand under a doorway so you’ll be under something that is not very likely to collapse. Also stay away from loose or hanging objects. Sitting or lying under a table is also something you can do so that things won’t hit you. Have a battery powered radio so you can here news about what is happening during the quake. You should also have battery powered flashlights so you’ll be able to see incase the electricity goes out. Always keep plastic water bottles in your house at all times because water pipes may explode. This is important to have because you need water and glass bottles will break. Another very important thing is to have canned food incase you are not able to get food, but don't forget the can opener! Overall, staying safe during an earthquake is very important.

Temblors have done so much destruction and have changed people’s lives. Through the studies of quakes we have learned many more things about tremors than the bad events they cause.

Sasha G and Lila R

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