Separation of intrinsic and scattering Q for volcanic tremor: an application to Etna and Masaya Volcanoes

The energy transfer theory in the hypothesis of 2-D isotropic multiple scattering is applied to the propagation of volcanic tremor. Under the assumption of a time stationary energy source, we calculate the pattern of energy vs distance as a function of intrinsic and scattering Q. Experimental values of attenuation coefficient 2 pif/Q measured at Etna and Masaya Volcanoes are fitted to the theory in order to contemporaneously estimate the loss of energy associated to scattering processes and that produced by intrinsic dissipation. Despite the high degree of trade off between the estimate of intrinsic and scattering attenuation deduced by the data analysis, results indicate that the tremor energy decay with distance is more strongly controlled by intrinsic dissipation than by scattering.