GEOL 101 Lecture Notes - Lecture 10: Retaining Wall, Mudflow, Ashwater
Term
Person
Theory
Place
Objectives:
● Define Natural Hazard and Natural Disaster
● Explain the basic characteristics of Natural Hazards
● Define Mass Wasting
● Describe the competing forces that cause materials to move
● Categorize the different types of Mass Wasting
● Outline the factors that control Mass Wasting and slope failure
● Outline ways to prevent slope failure
Natural Hazard: phenomenon with potential to cause death/damage
● Earthquake, volcano, flood, storms, landslides, mass wasting
Natural Disaster: when natural hazard causes significant damage to life/property
Characteristics of Natural Hazard
● Not randomly distributed
● When natural hazards coincide, they amplify the scope of the disaster
○ Earthquake causes landslide
● Unpredictable….for now!
● Magnitude of event is inversely proportional to its frequency
○ Larger the event, less likely it will happen
● Past events can create conditions that alter future events
Earth’s External Processes
● Surface processes are responsible for the movement and transport of Earth’s material
● Weathering: physical breakdown/chemical alteration of rock at/near the Earth’s surface
● Mass movement (wasting): transfer of rock/soil down slope under the influence of gravity
● Erosion: physical removal of material by mobile agents (water, wind, ice, gravity)
Mass Wasting
● Refers to downslope movement of rock, regolith, and soil under the direct influence of gravity
● Potential for death/destruction
● Lots of them! Wow! Not just landslides!
● Competing forces
○ Perpendicular (normal) to surface = contributes to friction
○ Parallel (shear) to surface = contributes to sliding
○ Gravity: pulls object towards earth’s center
○ Small amounts of water
■ Glue particles together (surface tension)
○ Lots of water
■ Reduces friction
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Explain the basic characteristics of natural hazards. Describe the competing forces that cause materials to move. Categorize the different types of mass wasting. Outline the factors that control mass wasting and slope failure. Natural hazard: phenomenon with potential to cause death/damage. Earthquake, volcano, flood, storms, landslides, mass wasting. Natural disaster: when natural hazard causes significant damage to life/property. When natural hazards coincide, they amplify the scope of the disaster. Magnitude of event is inversely proportional to its frequency. Larger the event, less likely it will happen. Past events can create conditions that alter future events. Surface processes are responsible for the movement and transport of earth"s material. Weathering: physical breakdown/chemical alteration of rock at/near the earth"s surface. Mass movement (wasting): transfer of rock/soil down slope under the influence of gravity. Erosion: physical removal of material by mobile agents (water, wind, ice, gravity) Refers to downslope movement of rock, regolith, and soil under the direct influence of gravity.