The response of an elastic system to an acoustic energy impulse describes a wavelet of several cycles of sinusoidal character At the onset, the wavelet will be rich in all frequencies but the high frequency components are attenuated rapidly by transit through earth materials because of inelastic absorption and conversion to heat
A limited series of waves caused by a periodic disturbance of short duration, e g , the radiofrequency waves in a single pulse, or a succession of pulses themselves