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Published byEfrain Harbolt Modified over 9 years ago
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UNDERSTANDING LANDSLIDES Dr. Walter Hays, Global Alliance For Disaster Reduction
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ESSENTIAL KNOWLEDGE FOR SOCIETAL SUSTAINABILITY A FRAMEWORK FOR UNDERSTANDING THE IMPACTS OF LANDSLIDES ON PEOPLE AND THEIR COMMUNITIES
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LANDSLIDES NATURAL PHENOMENA THAT OCCUR WITH OR WITHOUT HUMAN ACTIVITY
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FORCASTING FUTURE EVENTS The goal is recording, processing, and interpreting geologic changes in time frames of seconds to weeks; i.e., “real- time geology.”
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FORCASTING FUTURE EVENTS Predicting a large volume landslide is important for society, but it depends on long-term monitoring of individual slides.
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LANDSLIDES Falls, Topples, Slides, Spreads, Flows
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LANDSLIDE HAZARD Landslides encompass all categories of gravity-related slope failures in Earth materials.
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SLOPES Slopes are the most common landforms. Although they appear stable and static, slopes are actually dynamic, evolving systems.
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SLOPES Material is constantly moving on slopes at rates varying from imperceptible creep to thundering avalanches and rock falls moving at high velocities.
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LANDSLIDES Gravity slope failures are triggered by earthquake ground shaking or excess precipitation The slope does not need to be very steep for a landslide to occur.
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FORCASTING FUTURE EVENTS To predict when an earthquake will occur is important for society, but it is not yet feasible because earthquake prediction isn’t.
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LAHAR A lahar is a special “landslide” or mud flow induced by an explosive volcanic eruption.
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FORCASTING FUTURE EVENTS Predicting when a volcano will erupt is important for society, but it depends on knowledge of each volcano’s eruption history.
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MOUNT RANIER Mount Ranier has generated more than 60 lahars during the past 10,000 years. Many of these occurred during periods of volcanic quiescence.
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MOUNT RANIER Today, Mount Ranier continues to vent steam and convert its andesitic summit into clay. A plan to evacuate 50,000 people has been developed.
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LANDSLIDE HAZARD: ALASKA THE 1964 PRINCE WILLIAM SOUND EARTHQUAKE TRIGGERED A LARGE VOLUME LANDSLIDE AT TURNAGAIN HEIGHTS. MILLIONS OF CUBIC METERS OF SOIL AND ROCK MOVED DOWN SLOPE. THE 1964 PRINCE WILLIAM SOUND EARTHQUAKE TRIGGERED A LARGE VOLUME LANDSLIDE AT TURNAGAIN HEIGHTS. MILLIONS OF CUBIC METERS OF SOIL AND ROCK MOVED DOWN SLOPE.
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LANDSLIDE HAZARD: ALASKA Slope failure was induced by ground shaking of “Quick Clay.”
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LANDSLIDE HAZARD: ECUADOR
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LANDSLIDE HAZARD: JAPAN
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LANDSLIDE HAZARD: WASHINGTON STATE
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LATERAL SPREADING: JAPAN
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LATERAL SPREAD: SAN FRANCISCO
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