https://univ-rennes.hal.science/hal-02989177Ker, StephanStephanKerIFREMER - Institut Français de Recherche pour l'Exploitation de la MerLe Gonidec, YvesYvesLe GonidecGR - Géosciences Rennes - UR - Université de Rennes - INSU - CNRS - Institut national des sciences de l'Univers - OSUR - Observatoire des Sciences de l'Univers de Rennes - UR - Université de Rennes - INSU - CNRS - Institut national des sciences de l'Univers - UR2 - Université de Rennes 2 - CNRS - Centre National de la Recherche Scientifique - INRAE - Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement - CNRS - Centre National de la Recherche ScientifiqueFiltering of a Ricker wavelet induced by anelastic seismic wave propagation and reflectionHAL CCSD2020seismic attenuationQ factoranelasticityseismic data analysis[SDU.STU.GP] Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]Le Gonidec, Yves2020-11-05 11:57:222023-05-10 08:39:332020-11-17 09:14:50enJournal articleshttps://univ-rennes.hal.science/hal-02989177/document10.1093/jge/gxaa033application/pdf1A varying Q factor with depth induces modifications of seismic wave features due to anelastic propagation but also reflections at the discontinuities. Standard signal analysis methods often neglect the reflection contribution when assessing Q values from seismic data. We have developed an analytical quantification of the cumulative effects of both the propagation and reflection contributions by considering Kjartansson's model and a seismic plane wave at normal incidence on a step-like discontinuity. We show that the cumulative effects are equivalent to a frequency filter characterised by a bandform and phase that both depend on the ratio between the elastic and anelastic contrasts. When considering this filter applied to a Ricker wavelet, we establish an analytical expression of the peak-frequency attribute as a function of propagation and reflection properties. We demonstrate that this seismic attribute depends on the anelastic contrast, which cannot be neglected when assessing Q factors: the error in Q estimate is not linearly dependent on the anelastic contrast and we establish an analytical expression for the case where this contrast is weak. An unexpected phenomenon for a step-like interface is an increase in the peak frequency that is observed when the anelastic and elastic contrasts have opposite signs, with a constraint on the anelastic propagation properties. This behaviour allows for assessment of the elastic and anelastic parameters.