a group of persons, as employees, charged with carrying out the work of an establishment or executing some undertaking. a group of assistants to a manager, superintendent, or executive. a member of a staff.
Seismic waves are the waves of energy caused by the sudden breaking of rock within the earth or an explosion. They are the energy that travels through the earth and is recorded on seismographs. Types of Seismic Waves. There are several different kinds of seismic waves, and they all move in different ways.
The three types of seismic waves are primary waves, secondary waves and surface waves. Seismic waves can cause earthquakes and have destructive capability. Primary and secondary waves are known as body waves, and these waves penetrate the interior of the Earth, whereas surface waves do not penetrate the Earth. Continue Reading. Primary waves are also known as pressure waves and travel at the highest velocity inside the Earth.