# Dictionary:Q(Quality)

**1**. Quality factor, the ratio of 2π times the peak energy to the energy dissipated in a cycle; the ratio of 2π times the power stored to the power dissipated. The seismic *Q* of rocks is of the order of 50 to 300. *Q* is related to other measures of absorption (see below):

where *V*, *f*, *λ*, and *T* are, respectively, velocity, frequency, wavelength, and period.^{[1]} The absorption coefficient *α* is the term for the exponential decrease of amplitude with distance because of absorption; the amplitude of plane harmonic waves is often written as

where *x* is the distance traveled. The logarithmic decrement *δ* is the natural log of the ratio of the amplitudes of two successive cycles. The last equation above relates *Q* to the sharpness of a resonance condition; *f*_{r} is the resonance frequency and is the change in frequency that reduces the amplitude by . The damping factor *h* relates to the decrease in amplitude with time,

**2**. The ratio of the reactance of a circuit to the resistance.

**3**. A term to describe the sharpness of a filter; the ratio of the midpoint frequency to the bandpass width (often at 3 dB).

**4**. A designation for *Love waves* (q.v.).

**5**. Symbol for the *Koenigsberger ratio* (q.v.).

**6**. See *Q-type section*.

## See also

## References

^{[3]}

^{[4]}

^{[5]}

## External links

- ↑ Sheriff, R. E. and Geldart, L. P., 1995, Exploration Seismology, 2nd Ed., Cambridge Univ. Press.
- ↑ Sheriff, R.E., 1989,
*Geophysical methods*, pg. 330: Prentice Hall Inc. - ↑ Whaley, J., 2017, Oil in the Heart of South America, https://www.geoexpro.com/articles/2017/10/oil-in-the-heart-of-south-america], accessed November 15, 2021.
- ↑ Wiens, F., 1995, Phanerozoic Tectonics and Sedimentation of The Chaco Basin, Paraguay. Its Hydrocarbon Potential: Geoconsultores, 2-27, accessed November 15, 2021; https://www.researchgate.net/publication/281348744_Phanerozoic_tectonics_and_sedimentation_in_the_Chaco_Basin_of_Paraguay_with_comments_on_hydrocarbon_potential
- ↑ Alfredo, Carlos, and Clebsch Kuhn. “The Geological Evolution of the Paraguayan Chaco.” TTU DSpace Home. Texas Tech University, August 1, 1991. https://ttu-ir.tdl.org/handle/2346/9214?show=full.