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.
P and S waves. A wave is a vibration that transfers energy from one place to another without transferring matter (solid, liquid or gas). Light and sound both travel in this way. Energy released during an earthquake travels in the form of waves around the Earth. Two types of seismic wave exist, P- and S-waves.