An empirical classification scheme, based upon a length to thickness ratio, is developed to describe the geometric configuration of seismogenic zones as planar, tabular, or volumnar. That scheme is applied to 33 recent, high-quality studies of seismicity patterns and aftershock studies in the contiguous United States, Alaska, Canada, Nicaragua, Argentina, Guinea (West Africa), Algeria, Italy, Iran, and New Zealand. The classification results show that the majority (49%) of the seismogenic zones examined are volumnar, 39% are tabular, and only 12% are planar.