Measuring the forces generated by erosive debris flows

Apr 16, 2013

Like water flows, debris flows can carve out steep valleys and change landscapes. By studying the mechanics of bedrock incision caused by flowing debris, scientists are better able to understand patterns and rates of landscape evolution. Laboratory studies and models have shown how flowing granular materials can cut into rock, but field measurements are needed to confirm the findings and provide information about the more complex natural environment.

Monitoring a natural debris flow environment, McCoy et al. measured approximately 30-60 millimeters (1.2 to 2.4 inches) of bedrock lowering over a 4-year period. They observed the mechanisms by which the bedrock was removed by passing debris flows and analyzed the characteristics of several erosive debris flow events, focusing on the basal normal force—the downward force on the exerted by the flowing debris—which fluctuated substantially during the events due to particles entrained in the flow impacting the bed.

They also find that a of bed sediment can shield the bed from the impact of erosive particles. The findings, which allow the researchers to place constraints on the forces involved in the erosion process, show that debris flows are an important driver of landscape change.

Explore further: Thousands of intense earthquakes rock Iceland

More information: Field measurement of basal forces generated by erosive debris flows, Journal of Geophysical Research-Earth Surface, doi:10.1002/jgrf.20041 , 2013 http://onlinelibrary.wiley.com/doi/10.1002/jgrf.20041/abstract

add to favorites email to friend print save as pdf

Related Stories

Tsunami debris survey launched northwest of Midway

Jan 26, 2012

The tsunami that followed on the heels of the March 11, 2011, earthquake in Japan produced as much as 25 million tons of debris. Much of this debris was swept into the ocean. What stayed afloat drifted apart ...

Forest soil erosion in the wake of major bushfires

Nov 07, 2012

Researchers from Australia and the UK tracing soil in one of the areas affected in the 'Black Saturday' bushfires in Victoria have shown how nuclear science can explain the environmental impact of soil erosion.

Recommended for you

NASA sees Tropical Storm Lowell's tough south side

17 hours ago

The south side of Tropical Storm Lowell appears to be its toughest side. That is, the side with the strongest thunderstorms, according to satellite imagery from NOAA's GOES-14 and NASA-NOAA's Suomi NPP satellites.

User comments : 0