# Relation between nepers and decibels

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Series | Geophysical References Series |
---|---|

Title | Problems in Exploration Seismology and their Solutions |

Author | Lloyd P. Geldart and Robert E. Sheriff |

Chapter | 2 |

Pages | 7 - 46 |

DOI | http://dx.doi.org/10.1190/1.9781560801733 |

ISBN | ISBN 9781560801153 |

Store | SEG Online Store |

## Problem 2.17

The natural logarithm of the ratio of two amplitudes is measured in nepers. Show that one neper = 8.68 dB.

### Background

By definition, if and are energies, is the value of the ratio in bels. One bel = 10 decibels (dB), and energy is proportional to (amplitude), so

**(**)

### Solution

Let value measured in nepers, dB = same value in decibels. Then,

Since .

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Tube-wave relationships | Attenuation calculations |

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Introduction | Partitioning at an interface |

## Also in this chapter

- The basic elastic constants
- Interrelationships among elastic constants
- Magnitude of disturbance from a seismic source
- Magnitudes of elastic constants
- General solutions of the wave equation
- Wave equation in cylindrical and spherical coordinates
- Sum of waves of different frequencies and group velocity
- Magnitudes of seismic wave parameters
- Potential functions used to solve wave equations
- Boundary conditions at different types of interfaces
- Boundary conditions in terms of potential functions
- Disturbance produced by a point source
- Far- and near-field effects for a point source
- Rayleigh-wave relationships
- Directional geophone responses to different waves
- Tube-wave relationships
- Attenuation calculations
- Diffraction from a half-plane