How are seismic waves related to earthquakes?
When an earthquake occurs, rocks at a fault line slip or break, and two sections of Earth’s crust physically move relative to one another. That movement releases energy, and two types of seismic waves radiate outward from the earthquake through Earth’s interior and along its surface.
What causes an earthquake focus?
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. The spot underground where the rock breaks is called the focus of the earthquake.
What do you need to know about seismic waves?
Definition: What are Seismic Waves? Seismic waves are energy waves that are generated by an earthquake or explosion and propagate within the Earth or on its surface. Earthquakes occur when there is a movement of Earth’s tectonic plates. Seismic waves are studied by seismologists using an instrument called seismograph.
How is the focus and epicentre of an earthquake related?
The point inside the crust where the pressure is released is called the focus. The point on the Earth’s surface above the focus is called the epicentre. Earthquake energy is released in seismic waves. These waves spread out from the focus. The waves are felt most strongly at the epicentre, becoming less strong as they travel further away.
Where does the energy go during an earthquake?
Anatomy of an Earthquake. The point on the Earth’s surface directly above the focus is the epicenter. When energy is released at the focus, seismic waves travel outward from that point in all directions. There are different types of seismic waves, each one traveling at varying speeds and motions. It’s these waves that you feel during an earthquake.
Where are earthquakes most likely to be felt?
Earthquake energy is released in seismic waves. These waves spread out from the focus. The waves are felt most strongly at the epicentre, becoming less strong as they travel further away. The most severe damage caused by an earthquake will happen close to the epicentre.