%0 Journal Article %T Estimation of viscoelastic attenuation of real seismic data by use of ray tracing software: Application to the detection of gas hydrates and free gas %+ Domaines Océaniques (LDO) %+ Institute of Physics %A Bouchaala, F. %A Guennou, Claude %< avec comité de lecture %J Comptes Rendus Géoscience %I Elsevier %V 344 %N 2 %P 57-66 %8 2012-02-17 %D 2012 %R 10.1016/j.crte.2011.12.006 %K Viscoelasic attenuation %K Gas hydrates %K Free gas %K Ray tracing %K Atténuation viscoélastique %K Hydrates de gaz %K Gaz libre %K Tracé des rayons %Z Sciences of the Universe [physics]/Earth Sciences %Z Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] %Z Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph] %Z Environmental Sciences/Global ChangesJournal articles %X Analysis of P wave velocity profiles and seismic data recorded over the 2002 Hydratech cruise conducted in the Storegga region, North of Norway, has shown the existence of anomalies (a velocity decrease) in some layers of the medium. An elastic propagation model is not sufficient to explain clearly these anomalies, since the viscoelastic attenuation, represented by the quality factor QP, is sensitive to physical phenomena of geological media. The combination of the quality factor profile with the velocity profile leads to realistic explanations of these anomalies. In this article, we explain the procedure which we developed for determining the QP profile from the P wave velocity profile and the seismic data recorded during Hydratech cruise. Both the QP and velocity profiles indicate anomalies in the same layers. Based on previous studies, we interpret that these anomalies are being due to existence of gas hydrates and free gas within these layers. %G English %L insu-00769840 %U https://insu.hal.science/insu-00769840 %~ SDE %~ INSU %~ UNIV-BREST %~ CNRS %~ GIP-BE %~ LGO %~ CMM %~ GEO-OCEAN