Now we will look at schematic depictions of clastic dikes formed by the three primary processes. The schematic depictions immediately following focus on an overview of the morphology of the dikes and the field setting in which the dikes develop. Whereas the external morphology of dikes in a fine-grained cap (from the three primary mechanisms noted above) is normally tabular, the internal morphology is more varied and ranges from nearly structureless, to fining-upward, to tubular, to strongly tabular in the vertical direction. If the internal stratigraphy is strongly tabular, a dike having different grain sizes generally has formed within a pre-existing dike; this sequence can result from either a single earthquake or from earthquakes widely separated in time. Examples having different internal stratigraphies are scattered throughout this presentation.

7. The most common result of hydraulic fracturing is development of steeply dipping clastic dikes. Widths range from 1 mm to about 15 cm. Widths of 3 to 4 cm are especially common. Dikes formed by this mechanism often pinch upward.