15. Vertical section showing vented sand (white sand) with feeder dike. The 15- to 20-cm thickness of brown material at the top of the section, above the vented sand, is silt that has been deposited by floods since the earthquakes in 1811-1812. Schematic depiction is shown in the next slide. (Photograph and schematic depiction courtesy of Steven G. Wesnousky, University of Nevada.)