Surface wave holography

摘要: Surface waves have proven to be very useful in determining the properties of Earth’s crust and mantle. The traditional surface wave analysis consists two steps. First, from recordings, dispersion data (phase velocities or group velocities) are retrieved for each source receiver pair (Dziewonski Hales, 1972; Nolet, 1977). Next, information different frequencies many pairs is combined yield an image interior (e.g. Woodhouse Dziewonski, 1984; Montagner, 1986; Nataf et al., 1986). These methods implicitly use ray theory by resorting “great circle theorem” (Backus, 1964; Jordan, 1978; Dahlen, 1979). This theorem states that a sufficiently smooth medium only influenced structure under great joining receiver. acceptable provided inhomogeneity varies little on scale wavelength waves.