**5.2 Louisiana dome anomaly, USA**

A residual gravity map was acquired over a salt dome off the coast of Louisiana, USA ([41], Figures 8–20). The residual gravity anomaly profile [57] is redrawn across the center of the map, normal to the causal anomaly's striking. The residual gravity anomaly profile of about 13,000 m long was digitized at sampling interval of 200 m (**Figure 11a**).

#### **Figure 11.**

*The Louisiana dome anomaly, USA. (a) Gravity anomaly profile (red dotted lines) and the optimum-fitting model (solid black line), (b) Horizontal and vertical gradients of (a), (c) Analytic signal anomaly using the data of (b), and (d) 2-D mosaic of the R-parameter and the R-max value.*


### **Table 9.**

*The Louisiana dome gravity anomaly, USA. The R-parameter calculated from different shape factors.*


## **Table 10.**

*The Louisiana dome gravity anomaly, USA. The estimated parameters.*

By applying the R-parameter method procedures mentioned before to the residual gravity anomaly profile of Louisiana we get the available shape parameters corresponding to the maximum R-parameter (R-max) as shown in **Table 9**. **Figure 11b–d** shows the horizontal and vertical derivative anomalies, the amplitude analytic signal, and the R-parameter 2-D mosaic of the Louisiana anomaly. It is found that the R-max value is 0.96 corresponds to *q* = 0.9 which is approximated by horizontal cylinder shape. The best estimated model parameters are: *q* = 0.9, *z*<sup>o</sup> = 2950 m, *x*<sup>o</sup> = 400 m, and *A* = 3282.61 mGal m.

The Louisiana dome anomaly has been interpreted by different authors assuming a horizontal source to determine the depth to the center of the salt body. The obtained results have a good agreement with those depths to the center that obtained by the published literatures of [5, 41] (**Table 10**). In addition, the proposed method has the lowest misfit compared to the other method (**Table 10**).
