Do seismic waves sense fracture connectivity?

• Published in: Geophysical research letters 2013-02, Vol.40 (4), p.692-696
• Main Authors: Germán Rubino, J., Guarracino, Luis, Müller, Tobias M., Holliger, Klaus
• Format: Article
• Language: English
• Subjects: Compressibility; Computational fluid dynamics; Earth sciences; Earth, ocean, space; Energy loss; Exact sciences and technology; Fluid flow; Fluids; Fracture mechanics; fractured rocks; Geophysics; Hydraulic properties; Hydraulics; numerical simulations; Plate tectonics; porous media; Rocks; seismic attenuation; Seismic waves; Seismology
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1002/grl.50127

A defining characteristic of fractured rocks is their very high level of seismic attenuation, which so far has been assumed to be mainly due to wave‐induced fluid flow (WIFF) between the fractures and the pore space of the embedding matrix. Using oscillatory compressibility simulations based on the quasi‐static poroelastic equations, we show that another important, and as of yet undocumented, manifestation of WIFF is at play in the presence of fracture connectivity. This additional energy loss is predominantly due to fluid flow within the connected fractures and is sensitive to their lengths, permeabilities, and intersection angles. Correspondingly, it contains key information on the governing hydraulic properties of fractured rock masses and hence should be accounted for whenever realistic seismic models of such media are needed. Key Points Wave‐induced fluid flow effects in fractured rocks are comprehensively simulated A new manifestation of wave‐induced flow due to fracture connectivity is found Additional seismic energy loss is produced by flow within connected fractures