pynetdesign.modelling.utils.phase_radiation_pattern#
- pynetdesign.modelling.utils.phase_radiation_pattern(phase)[source]#
Return the root-mean-square radiation-pattern magnitude of a phase.
The values are averages over the focal sphere of a double-couple source [Boore and Boatwright, 1984], as used for microseismicity with random source orientations [Hallo and Eisner, 2013]:
\[R_P = \sqrt{4/15} \approx 0.52, \quad R_{SV} = \sqrt{7/30} \approx 0.48, \quad R_{SH} = \sqrt{1/6} \approx 0.41.\]- Parameters:
- phase
str Phase, one of
'P','SV'or'SH'.
- phase
- Returns:
- rad_pattern
float Radiation-pattern magnitude of the phase.
- rad_pattern
- Raises:
- ValueError
If
phaseis a composite mode rather than a single phase.
Notes
The value \(\sqrt{2/5} \approx 0.63\) often quoted for S-waves is the magnitude of the combined S-wave amplitude, since \(\langle R_{SV}^2 \rangle + \langle R_{SH}^2 \rangle = 2/5\), and is therefore not applicable to SV or SH individually.