Earthquakes are caused by the buildup of tension (energy) between tectonic plates. An Earthquake occurs when the tension is released and seismic waves are what you feel as the energy passes through the earth's crust.
The most active fault lines in the United States are along the Pacific Ocean: Up the coast of California, Oregon, Washington and Alaska.
This area is part of the Ring of Fire - an area of increased volcanic and earthquake activity around the Pacific Ocean. Ninety percent of the world's earthquakes and 80% of the world's largest earthquakes occur along the Ring of Fire.
The most major earthquakes tend to occur at subduction zones. When a subducting slab (or a portion thereof) becomes locked in place, very very large stresses can from in the locked portion of the crust over a very long portion of the subduction zone storing a very large amount of energy. When the stress exceeds the strength of the rockmass, the fault ruptures "unlocking" the previously locked zone allowing it to move again and commonly causing very large thrust faults to form. This releases the very large amounts of energy stored in the crust as seismic waves.
These types of very large earthquakes that occur at subduction zones are known as megathrust earthquakes and are responsible for some of the most powerful ever recorded, including the 1960 magnitude 9.5 Valdivia earthquake in Chile, the 1964 magnitude 9.2 Alaskan earthquake and the 2004 Indian ocean earthquake.
The major cause of earthquakes is when the earth's plates shift and grind against each other, or when they get caught on each other and jerk apart releasing energy.
Answer 1 =Tectontic plates. that is what causes earthquakes, but earthquakes are causes of sliding boundaries.
Answer 2 = An earthquake basically means a series of shock waves generated at a point or focus within the Earth, the point on the surface of the Earth above the focus being termed the earthquake epicentre. An earthquake is basically caused by the movement of rocks on a break in the continuity of a body of rock or of a vein where theren is dislocation along the plane of the fracture known in geology as a fault plain, which results in the release of stored strain energy in the rocks due to Earth's lithosphere being divided into large rigid blocks termed Tectonic plates floating on semifluid rock and so able to interact with each other at their boundaries.
The length of the fault along which the dislocation happens may be up to several hundred kilometres, and the orientation of the fault plane may be anything from vertical to horizontal. But vertical planes are the most common. The depth commonly will be between 1 and 10 kilometres. Elastic energy radiates outwards from an earthquake in four distinct types of waves:-
1. P Waves : compression dilation waves similar to siund waves with a high frequency and short wavelength which travel through the solid outer part of the earth and through the core.
2. S Waves: transverse shear waves with a high frequency and short wavelength, rather like a rope being shaken along the ground which only travel through the solid outer part of the earth and not through the core.
3. L waves : Low frequency long wavelength transverse vibration confined to upper part of crust.
4. Rayleigh waves : Surface waves developed close to the epi-centre which cause a rolling wave-like motion of the surface.
It is the two latter surface waves that are responsible for most of the destruction an earthquake causes. The P and S Waves travel through the body of the earth at spoeeds proportional to the density of the medium and may be picked up at rather greater distances from the focus by seisometers.
Major earthquakes are associated with the edge of the plates that make up the Earth's crust as well as along the mid-oceanic ridges where new crusts are forming.
The greatest concentration of earthquakes is in the belt around the Pacific Ocean (known as the Ring of Fire), and also along a zone from the Mediterraneanto the Himilayas and China. The magnitude of any earthquake is measured on the Richter Scale.
Earthquakes happen the most on fault lines, the same as anywhere else in the world. The most major fault line in the US is the San Andreas Fault, located in the middle of California, also streching through some parts of Alaska. The fault has had some major earthquakes.
About 100 earthquakes per day are centered in Alaska
There are still some more minor fault lines in the US that aren't nearly as active, but another common place for earthquakes is the Missouri-Illinois-Indiana-Kentucky-Tennessee-Arkansas border.
Go to the website of the United States Geological Survey (USGS), it has up to the minute data on earthquakes in any area of the world and it also breaks them down into different strengths on the Richter scale.
plates grinding past each other along active faults
the three main causes of earthquake are:-
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Yes. Earthquakes occur most often along fault lines. There are also many different devices (seismograph) that sense seismic waves and can predict earthquakes.
There are so many earthquakes on the west coast because the west coast is between tectonic plates. These plates move and cause earthquakes.
Extremely few. Most earthquakes happen in the ocean, or too far below the crust for us to feel them, but hundreds happen every week.
This is debatable, but the three worst earthquakes in the U.S. were likely the San Francisco earthquake of 1906, the Alaskan earthquake of 1964, and the New Madrid, Missouri earthquake, which was in the early 19th century.
Alaska is the most prone to earthquakes in the US.
Earthquakes can occur anywhere, although they are more common near the oceans than further inland.
the majority of earth quakes in the USA occur in California and in Alaska
Missouri
Between 3000-4000
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where cracks in the earth's plates connect. it is because the earth is constantly moving from the rotation of orbit causing plates to shift & make earthquakes
Yes. Earthquakes occur most often along fault lines. There are also many different devices (seismograph) that sense seismic waves and can predict earthquakes.
I know some Tornadoes,hurricanes,volcanoes,blizzards,accidents,Earthquakes
The most earthquakes occur in Alaska, followed by California.
There are so many earthquakes on the west coast because the west coast is between tectonic plates. These plates move and cause earthquakes.
Extremely few. Most earthquakes happen in the ocean, or too far below the crust for us to feel them, but hundreds happen every week.