# Acceleration of Phase

**Attribute Description:** This measures the rate of change for instantaneous phase

**Interpretation Use:** This attribute may provide value by

- Accentuating bedding differences
- Higher Resolution may have a higher noise level due to differentiation
- May reflect some elastic properties of resolvable beds

**Recommended Colorbar:**

Since the distribution of this data is gaussian with spikes at the extremes, a normal seismic colorbar can be used to visualize this attribute – it will show a contrast between “Peaks” and “Troughs” and highlight them against the central data. A phase colorbar with common colors at peak and trough zones can also be used and will emphasize the central data more.

In this example, we are using a black – white – red colorbar.

Note that a phase based colorbar could also be used.

**Example:**

**Computation: **Acceleration of Phase (cycles/sec/sec) is based on instantaneous acceleration. The time derivative of instantaneous frequency/wavenumber, by definition, gives the instantaneous acceleration. This can be computed both from instantaneous frequency/wavenumber and from time averaged instantaneous frequency/wavenumber. It is obvious that the time derivative of instantaneous frequency/wavenumber will accentuate the local frequency/wavenumber jumps, and hence will make the thin bed indicators more prominent. It should also indicate to some degree the effect of absorption by showing the frequency/wavenumber dispersion of seismic signals going through unconsolidated or quickly deposited layers:

The corresponding value in depth domain is calculated as the second derivative of phase with respect to depth:

**References:**

- Chopra, S. and K. J. Marfurt, 2007, Seismic attributes for prospect identification and reservoir characterization: Society of Exploration Geophysicists, Geophysical Developments #11.
- Taner, M. T., 2001, Seismic attributes: Canadian Society of Exploration Geophysicists Recorder, 26, no 7.