We analyze the amplitude variation as a function of reflection angle (AVA) for angle-domain common image gathers (ADCIG) produced via wave-equation migration. Straightforward implementations of the two main ADCIG methods lead to contradictory, thus inaccurate, amplitude responses. The amplitude inaccuracy is related to the fact that downward-continuation migration is the adjoint of upward-conti...

In this report, we introduce a new wave-equation method of migration velocity analysis (MVA). The method is based on the linear relation that can be established between a perturbation in the migrated image and the generating perturbation in the slowness function. Our method consists of two steps: we first improve the focusing of the migrated image and then iteratively update the velocity model ...

This talk describes some applications of two kinds of observation estimate for the wave equation and for the damped wave equation in a bounded domain where the geometric control condition of C. Bardos, G. Lebeau and J. Rauch may failed. 1 The wave equation and observation We consider the wave equation in the solution u = u(x, t)    ∂ t u−∆u = 0 in Ω× R , u = 0 on ∂Ω× R , (u, ∂tu) (·, 0) = (u...

In the present work, treating the arteries as a thin-walled and prestressed elastic tube with a stenosis and the blood as a Newtonian fluid with negligible viscosity, we have studied the amplitude modulation of nonlinear waves in such a composite system by use of the reductive perturbation method. The governing evolution equation was obtained as the variable coefficient nonlinear Schrödinger (N...