7material from a single eruptive (nonsustained) eruption, such as a single blast or column collapse. The scale of turbulence and current thickness is greatly exaggerated in order to show dividing streamlines. a. Blocking of high concentration basal part of the transport system. Diverted flows move downstream at angles to the plane of section. b. Downslope drainage of rapidly accumulating depositional system. c. Secondary pyroclastic flows in valleys developed from runoff of depositional system and blocking of high concentration parts of the current. d. Dividing streamlines demarcating density stratification leading to decoupling.