The correct answer is seismic waves.
A sudden movement of the Earth's crust followed by the production of seismic waves is known as an earthquake. The seismic waves travel outwards from the source. The sudden vibration or ground motion is generated due to a brisk discharge of accumulated energy.
The vibrations, which travel via Earth carrying the energy discharged at the time of an earthquake is known as seismic waves. The earthquakes are usually determined with a help of seismometer, called seismograph.
