Gulf of Mexico, Walker Ridge

The 3D SJI workflow started from an existing seismic reflection tomographic model from which we removed a portion of the salt (top right) obtaining the initial velocity model and ran several iterations of targeted 3D SJI with reflection seismic and (marine magnetotelluric) MMT data, obtaining the final SJI velocity model (bottom right) together with its corresponding resistivity model. The bottom left image shows how the 3D SJI has led to a new 3D interpretation of the allochthonous salt base (colored) and positioning of the autochthonous top salt (blue).

A legacy wave-equation migration image overlaid by the velocities obtained with the legacy reflection tomography (left), and the new SJI velocity model (middle: updates from initial model, blue is low and red is high update) with interpretations (right).

The high velocity of autochthonous salt is absent in the single-domain velocity model (left) and present only in the SJI velocity model (middle and right) given the MMT capability of seeing the resistive salt anomaly.