A concave-upwards depression in a reflector with a curvature greater than that of an incident wave front is represented on a brute stack by a ‘bow-tie’ event. This results from there being three reflection points on the reflector for each surface location. A high degree of reflector curvature is required for each ‘bow-tie’ event to feature on normal incidence traces, with a reduced degree of curvature needed for a similar effect on offset traces. Consequently, ‘bow-tie’ events are more likely on long-offset traces and at greater depth within the seismic section. Curvature of the reflector out of the plane of the section can cause off-section ‘bow-tie’ ghosts.