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Volcano Web Shorts 2: Debris Flows

4 minutes

(Describer) Title: USGS – Science for a changing world.

(Describer) Quick scenes show work at laboratories and footage of giant plumes of ash rising from a volcano.

(Describer) Waves and colors are reviewed on many computer screens. Title: Volcano Web Shorts Number 2 – Debris Flows

My name is Richard Iverson. I am a research hydrologist at the U.S. Geological Survey Cascades Volcano Observatory here in Vancouver, Washington.

(Describer) A river of mud rushes.

My work focuses particularly on the dynamics of debris flows, debris avalanches, and other mass movements that occur at volcanos and also can occur in other settings. Debris flows are masses of rock and mud and water that travel rapidly down slopes and down stream under the action of gravity. Volcanos are a particularly ripe setting for large debris flows and debris flow disasters, partly because they're these huge steep piles of rubble. There's nearly an infinite supply of loose debris that can possibly get involved in one of these flows. It's important to realize that the hazard around volcanos, like those we have in the Northwest, goes well beyond the immediate environs of the volcano. It extends well downstream in lowlands areas, as much as 100 kilometers away from the volcano, as a result of these long-travel debris flows.

(Describer) Hazard Zonation maps are shown.

The goal of the research group I lead is quantitative forecasting of hazards from debris avalanches and debris flows. That work involves several components. There's a field component that entails simply observing and measuring what happens when these events occur naturally in the field. There's a laboratory experimentation component that involves making artificial debris flows at our USGS debris-flow flume. Then there's a mathematical modeling component, part of which involves actually deriving appropriate equations to describe the behavior. Then there's the task of solving those equations and portraying predictions on a computer. The experimental component of our work is conducted largely at a facility called the USGS debris-flow flume. This is basically a huge concrete chute built on a steep hillside about 50 miles east of Eugene, Oregon. At this facility, we mix up batches of debris that are very similar to natural debris in debris flows and then let them flow down the chute from a distance of about 100 meters. We can make many measurements under controlled conditions. It additionally allows us to repeat the experiment to make sure that we're getting replicable results. Without that kind of experimental testing, it would be difficult to know whether our models are performing well. Some of our models have been used extensively, worldwide, for making long-range hazard forecasts and also sometimes implemented in sort of an emergency situation. That's gratifying seeing that the science has that kind of practical application. This work really leads to saving of lives and additionally to protection of property to some degree.

Funding to purchase and make this educational production

(Describer) Titles: A production of USGS Volcano Hazards Program, USGS Office of Communications and Publishing Funding to purchase and make this educational program accessible was provided by the U.S. Department of Education. Contact the Department of Education by telephone at 1-800-USA-LEARN, or online at www.ed.gov.

accessible was provided by the U.S. Department of Education:

PH: 1-800-USA-LEARN (V) or WEB: www.ed.gov.

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Debris flows are hazardous flows of rock, sediment, and water that surge down mountain slopes and into adjacent valleys. Hydrologist Richard Iverson describes the nature of debris-flow research and explains how debris flow experiments are conducted at the United States Geological Survey (USGS) Debris Flow Flume in Oregon.

Media Details

Runtime: 4 minutes

Volcano Web Shorts
Episode 1
3 minutes
Grade Level: 9 - 12
Volcano Web Shorts
Episode 2
4 minutes
Grade Level: 10 - 12
Volcano Web Shorts
Episode 3
3 minutes
Grade Level: 10 - 12
Volcano Web Shorts
Episode 4
4 minutes
Grade Level: 9 - 12
Volcano Web Shorts
Episode 5
3 minutes
Grade Level: 9 - 12
Volcano Web Shorts
Episode 6
3 minutes
Grade Level: 10 - 12