Wave shoaling and the angular frequency is proportional to its local rate of change, Simplifying to one dimension and cross-differentiating it is now easily seen that the above definitions indicate simply that the rate of change of wavenumber is balanced by the convergence of the frequency along a ray; Assuming stationary conditions (formula_27), this implies that wave crests are conserved and the frequency must remain constant along a wave ray as formula_28. As waves enter shallower waters, the decrease in group velocity caused by the reduction in water depth leads to a reduction in wave length formula_29 because the nondispersive shallow water
Coda Wave Interferometry The unperturbed travel time is given by formula_8 where formula_9 is the coda wave velocity. The perturbed travel time is formula_10 where formula_11 is the velocity perturbation. Thus formula_12 . If the relative velocity perturbation is assumed constant, then formula_13 where t is the center time of the employed time window. Thus, the travel time perturbation depends on the arrival time of the coda wave, but not of the particular path followed. Coda Wave Interferometry Coda Wave Interferometry is an ultrasound technique for detection of weak and local changes in complex inhomogeneous media. Sound waves that travel through a medium