Subaqueous Confined Debris Flows
Subaqueous Confined Debris Flows Movies from Gary Parker, St. Anthony Falls Hydraulic Laboratory, University of Minnesota.
This series shows the role of small changes in abundance of clay in debris flow behavior within the confines of a flume. Scale is in meters. Shown weakest to strongest:
First flow: Turbidity current comes out of the top of the debris flow as it pushes through the standing water. Material falling out of the turbid suspension settles on top of, and is moved by, the debris flow. Carefully watch inside the flow to see the flow freezing from the base up, along discrete shear plains.
Second flow (starts @ 24 seconds): This flow has a relative increase in water and clay abundance, and so is finer grained overall than the previous flow.
Third flow (starts @ 35 seconds): Note the increase in the abundance of bentonite clay to 3%. Starting at 47 seconds, note tension cracks that develop in the upper, clayey, surface layer of the flow.
Fourth flow (starts @ 1:11): A slight increase to 4.5% bentonite. Note plug-like flow.
Fifth flow (starts @ 1:26): A slight increase to 6% bentonite results in a very rigid plug-like flow, with plastic deformation (roll over) at snout. Note very little secondary turbidity flow, since very little water flushes through the deposit.
File 31386 is a 11MB Quicktime MP4 Video
Uploaded: Jan20 12
Last Modified: 2012-01-20 14:55:45