Imaging three dimensional lithospheric structure using micro-earthquakes: High resolution seismic tomography
Archambeau, C.; Kohl, B.
published: Jul 31, 1996
ArtNo. ESP136000602010, Price: 19.00 €
New seismic techniques, utilizing signals from the large numbers of micro-earthquakes occurring in tectonically active areas, can now provide detailed 3-D seismic velocity structure images and 3-D "maps" describing on-going tectonic deformation. The deformation is expressed in terms of spatial variations in the magnitude of the stress released by micro-earthquake fracturing, the spatial variations in total strain energy release by brittle fracture and also in terms of the 3-D determination of the (time dependent) energy release levels from rapid creep deformation along faults. Taken together, the seismic velocity structure and the spatial definition of the tectonic state of the medium can be used to characterize the physical properties of the (composite) material and its deformational strain state and to define the large scale faulting dynamics within the medium. Further, in most cases it should be possible to infer the presence of ancient (currently inactive) faults from the detailed velocity structure, so that both a history of past tectonic activity and a definition of current activity can be obtained. This material state and tectonic state information can then be used to infer the presence of mineral deposits based on correlations of imaged intrusive bodies and other structural features (faults, folds, etc.) with the intrinsic material properties inferred from seismic velocity and other material parameter determinations.