Data Services Products: Surface-Wave Radiation Patterns – Interactive Plots

The surface-wave radiation pattern depends on the source process and therefore on the components of the moment tensor, on the depth of the earthquake, and on the frequency of the seismic waves. This website calculates the radiation pattern for any combination of these variables for both Rayleigh and Love waves. Further ExplanationsThe radiation patterns are displaying spectral amplitudes in [m/Hz] which have been calculated for continental lithosphere using the Earth model iasp91. Due to its discontinuities at 20 and 35km, the radiation patterns change abruptly at these depths.

The focal mechanisms for the earthquakes have been obtained from the Global CMT Project. We assume the event origins to be point sources in space and time and hence, all radiation patterns have a vanishing half-duration and directivity is not taken into account.

In accordance with the Global CMT Project, the moment magnitude is calculated for the double-couple component of the moment tensor only and will hence be smaller than expected for moment tensors with large isotropic components.

Pure doule-couple sources may be described by the strike, dip and slip angle of the fault on which the earthquake occurs. This calculator may be used to calculate the moment tensor components for pure double-couple sources and their surface-wave radiation patterns.