“…In Figure 1 we compare three filters, namely the total horizontal derivative (THDR, Cordell and Grauch, 1985), the normalized maximum horizontal gradient amplitude (TDX, Cooper and Cowan, 2006), and the tilt angle of the total horizontal gradient (TAHG, Ferreira et al, 2013), with the Signum transforms of the first and the second vertical derivative. We use a model composed of two dykes with a = 100 m (for both), and h = 100 m (left) and h = 500 m (right).…”