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A controlled in‐situ investigation of the relationship between stress, velocity and induced seismicity
Author(s) -
Maxwell S. C.,
Young R. P.
Publication year - 1995
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/95gl00885
Subject(s) - geology , perpendicular , induced seismicity , seismology , wave velocity , excavation , seismic velocity , stress (linguistics) , p wave , ultimate tensile strength , geotechnical engineering , geometry , petrology , materials science , composite material , linguistics , shear (geology) , medicine , philosophy , mathematics , cardiology , atrial fibrillation
A p‐wave velocity survey was performed after the excavation of a cylindrical, horizontal tunnel through homogenous, visibly unfractured granite. An image of the velocity structure around the tunnel indicated a distinct zone of high velocity corresponding to a zone of increased elastic stresses, where a break‐out notch formed. Perpendicular to this zone, a region of decreased velocity was found associated with a region of tensile elastic stress. The stress changes are believed to have preferentially opened and closed pre‐existing micro‐fractures in the rock, thereby decreasing and increasing the p‐wave velocity. Additional velocity decreases are also attributed to creation of new fractures. The excavation‐induced microseismicity is found to be generally associated with the high‐velocity region adjacent to the notch, and appears to be located along the boundary between the fractured, low‐velocity and high‐velocity regions.