42. This slide shows a common phenomenon in which the clastic infilling in a dike has very different grain sizes that are separated by a sharp vertical boundary. This photograph is a vertical view of a portion (near the base) of a 0.5-m-wide lateral spread in the banks of the Wabash River, which developed in the earthquake of 6,100 yr BP. A 8- to 15-cm-wide dike of medium sand cuts into coarser sand that was previously intruded. There is only slight weathering in the two sizes of sand. At this location, the two sand sizes represent liquefaction from different source beds at depth, from the same earthquake.

Even small dikes commonly contain dikes that have formed within one another, from the same earthquake.