Least-squares reverse time migration for the Cascadia ocean-bottom dataset

Conventional mirror imaging

The essence of conventional mirror imaging is to account for the kinematics of the mirror signal (Figure 2 (a)) by placing the receiver position at twice the ocean depth above the seabed. If the sea surface is a perfect reflector with a reflectivity of -1, then the simulated mirror migration path (Figure 2 (b)) will be equivalent to the mirror signal.

One advantage with mirror imaging is that the mirror's illumination aperture is much wider than that of the primary signal. Another advantage is that mirror imaging can be easily adapted to existing migration algorithms by changing the receiver position.

Figure2
Figure 2. (a) The raypath of a mirror signal. (b) The raypath of the same signal in mirror imaging. The apparent position of the receiver is now at twice the ocean depth above the seabed. This assumes the sea surface is a perfect reflector.

Least-squares reverse time migration for the Cascadia ocean-bottom dataset