What causes earthquakes?
Earthquakes occur when two tectonic plates collide or slide past each other. When the pressure between the two plates has built up over time until there is enough pressure built up for the tectonic plates to suddenly slide past or collide. The focus point of the earthquake where all of this pressure is building up underground is called the hypocenter. The point above ground where the focus of the earthquake is is called the epicenter. When the tectonic plates collide or slide past each other, the epicenter and the hypocenter send our waves. When the pressure is released, the strain causes brittle rock to crack, these cracks are called faults, to know more about faults, please go to the plate movement and faults slide.
What are the waves? And are there different kinds.
There are 3 different types of seismic waves (earthquake waves). There are body waves that penetrate the earth and move through it and there are surface waves that travel along the surface of the ground.
What are the waves? And are there different kinds.
There are 3 different types of seismic waves (earthquake waves). There are body waves that penetrate the earth and move through it and there are surface waves that travel along the surface of the ground.
The first waves that are felt in an earthquake are P waves. Primary waves are one of the Body waves.
Primary waves produce a back and forth motion/compress as they travel along the surface. They can also cause the ground to fracture and buckle. These waves are sent out of the hypocenter and the epicenter at the same time as the other body wave but Primary waves travel faster.
Primary waves produce a back and forth motion/compress as they travel along the surface. They can also cause the ground to fracture and buckle. These waves are sent out of the hypocenter and the epicenter at the same time as the other body wave but Primary waves travel faster.
The second waves felt in an earthquake are the other type of body waves called secondary waves (also known as shaking waves or shear waves). Secondary waves are more destructive than Primary waves because they have a higher amplitude and have an up and down and sideways motion. Secondary waves can only travel through rock but not liquid and other types of state.
To see how a Secondary waves moves click on this link here:http://www.geo.mtu.edu/UPSeis/images/S-wave_animation.gif
To see how a Secondary waves moves click on this link here:http://www.geo.mtu.edu/UPSeis/images/S-wave_animation.gif
Surface waves: surface waves are similar to nature's water waves, they travel just under the Earths surface. Typically they are generated when the source of the earthquake is near to the surface of the Earth. Surface waves travel slower than Secondary and Primary waves but they have a much higher amplitude and are the waves that causes the most destruction. There are 2 different main types of Surface Waves.
1) The Rayleigh waves(also called ground roll). Rayleigh waves travel in ripples similar to waves on the surface of the water. People in earthquakes with Rayleigh waves claimed to have seen them during the earthquake in wide open spaces where the cars move up and down with the waves. 2) Love waves: Love waves have the same movement as the Secondary waves apart from the fact that they have no vertical displacement. The amplitude of this motion decreases with depth. Love waves cause the rocks they pass through to change shape. They move the ground from side to side and that can damage buildings.
1) The Rayleigh waves(also called ground roll). Rayleigh waves travel in ripples similar to waves on the surface of the water. People in earthquakes with Rayleigh waves claimed to have seen them during the earthquake in wide open spaces where the cars move up and down with the waves. 2) Love waves: Love waves have the same movement as the Secondary waves apart from the fact that they have no vertical displacement. The amplitude of this motion decreases with depth. Love waves cause the rocks they pass through to change shape. They move the ground from side to side and that can damage buildings.
If these seismic waves are created under water, it will create a Tsunami.