Upload File

mass movements. smith chapter 8 mass movements downslope movement of large volumes of surface...

  • Home
  • Documents
  • Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
79
Mass Movements

Upload: noreen-pope

Post on 28-Dec-2015

220 views

Category:

Documents


2 download

Report

Tags:

TRANSCRIPT

Page 1: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Mass Movements

Page 2: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Mass Movements

• Smith Chapter 8

Page 3: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 4: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 5: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Mass Movements

• Downslope movement of large volumes of surface materials under gravity

Page 6: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Mass Movements

• Vary in speed– rapid movements can kill– slower movements can be costly

• soil creep, subsidence

Page 7: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Mass Movements

• Vary in materials– Landslides

• Rockfalls

• Mudflows

– Avalanches

Page 8: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Mass Movements

• Triggered– weather– earthquake, volcano– vibration

Page 9: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Mass Movements

• Risk increasing as land-hunger forces development of unstable & steep slopes

Page 10: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Germi, Iran

Page 11: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 12: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 13: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 14: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Mass Movements

• Early 1970s: produced around 600 deaths/year

• Late 1980s: several thousand annually

• Most deaths in Third World– USA: annual death toll 25-30

Page 15: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 16: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Mass Movements

• Annual losses in the billions US$ each year– especially in cities

• US$1-3 bn/year in the USA– Appalachian, Rocky Mtns, Pacific

• US$500 million in LA area from landslides in an el Nino year

Page 17: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Mass Movements

• Most deaths on Pacific Rim– associated with seismic activity– high population densities– heavy typhoon rainfall– rapid economic development

Page 18: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Mass Movements

• Increased by shanty-town settlement– on steeper, less-stable slopes

Page 19: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Caracas, Venezuela

• 1950s: fewer than 1 urban landslide/year

• City expands rapidly, esp. in 1970s

• Shanties spread out onto hills

• 1980s: 35-40 urban landslides/year

Page 20: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

High landslide hazard: Guatemala City

Page 21: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

La Paz, Bolivia

Page 22: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 23: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 24: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 25: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Avalanches

• Common on snow-covered slopes steeper than 20 degrees, less than 60 degrees

• Move at 80m/s (288 km/h)

• Settlement needs to avoid the runout tracks

Page 26: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Avalanches

• Frequent but usually harmless– USA 7,000-10,000 avalanches/year, only 1%

cause harm

• Threat to unwary travellers, badly-sited settlements

• Risks increased by alpine tourism development

Page 27: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Lake Tahoe CA

Page 28: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Avalanches

• More avalanche deaths in Europe– higher population density– Switzerland 25-30 deaths/year

Page 29: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 30: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 31: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Intense Landslide Risk

• High mountains– Areas of seismic shaking– High relief

• Soils made erodible by deforestation

• Thick deposits of fine-grained loosely-packed material

• Areas of high rainfall

Page 32: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 33: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Ganges delta

Page 34: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Unstable slopes, Nepal

Page 35: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Rohtang pass, India

Page 36: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 37: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 38: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 39: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Auguas Calientes, Peru

Page 40: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Rail line serving Maccu Piccu

Page 41: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Huascaran Peru

Page 42: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

• Monument to the dead of Yungay

Page 43: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Yungay school bus

Page 44: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Frank Slide AB, 1903

• Rockfall caused by natural weathering of anticlinal rocks of Turtle Mountain

• Triggered by spring freeze-thaw

• Undercut by mining

• Destroyed Frank townsite

• Killed 70

Page 45: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Frank slide AB

Page 46: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 47: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 48: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Hope slide BC

Page 49: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 50: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 51: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Soil Mechanics

• Slopes fail when shear strength of slope is exceeded– excessive loading– cohesion failure of slope materials

Page 52: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Soil Mechanics

• Different configurations of slide– rotational– translational

Page 53: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Lake Merced 1967

Page 54: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Lake Merced 1967

Page 55: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Ground subsidence

Page 56: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Debris flows

• Slope materials become fluidised– saturated– follows natural drainage channels– great destructive force

• Very common in the wet tropics

Page 57: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 58: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 59: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 60: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

China: Guangxi

Page 61: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 62: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Brazil 1991: 15 killed

Page 63: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Bhutan after monsoon

Page 64: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 65: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 66: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 67: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

NZ west coast

Page 68: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

NZ landslide hazard

Page 69: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

How to trigger a landslide

• Make slope steeper– undercut it– add material

• Add weight to the slope

• Add water to the slope (very effective)

• Remove vegetation

• Provide vibrations and shocks

Page 70: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Aberfan 1966

• Coal-mine waste dump collapses on Welsh village

• Destroyed several homes and primary school during morning assembly

• Killed 140+, – including 111 children

Page 71: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 72: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 73: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 74: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Aberfan 1966

• Hazard noted in 1920s

• Mine dump not engineered

• Receiving wet slurry in 1966

• Village and primary school in harm’s way

• School principal had complained of the dangers, her protests were ignored

Page 75: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Reducing landslide risks

• Careful settlement siting

• Slope stabilisation

• Slope drainage modification

• Slope vegetation

• Revetments, slope freezing (temporary)

Page 76: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 77: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity
Page 78: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Reducing avalanche risks

• Trigger avalanches at safe times– smaller avalanches– with explosives, artillery

• Defensive structures

• Careful settlement siting

Page 79: Mass Movements. Smith Chapter 8 Mass Movements Downslope movement of large volumes of surface materials under gravity

Avalanche defences


Objectives - Winston-Salem/Forsyth County Schools · Objectives • Identify factors ... Mass Movements, Wind, and Glaciers • Relate how mass movements affect people. ... mass movement

Objectives - Winston-Salem/Forsyth County Schools / … • Identify factors that affect mass movements. Mass Movements, Wind, and Glaciers • Relate how mass movements affect people

Mass Movements - Tulane Universitysanelson/eens1110/massmovements.pdf · Mass Movements Mass movements ... zRock Slides and Debris Slides - Rock slides and debris slides result when

Mass Movements/ Mass Wasting - hamburgschools.org · Mass Movements/ Mass Wasting Slope failure near McClure Pass, ... landslides, slump, earthflows, mudflows, ... along slip planes

Mass Movements at Earth’s Surface · MASS MOVEMENTS Mass movement: downslope movement of loose sediments and weathered rock resulting from the force of gravity All occur on slopes;

Mass Movements. Mass Movement - The transfer of rock and soil downslope due to gravity

8.1 Mass Movements

Objectives Identify factors that affect mass movements. Mass Movements, Wind, and Glaciers Relate how mass movements affect people. Analyze the relationship

PART 1 Mass Movements at Earth’s Surface. Mass Movements Mass movement: downslope movement of loose sediments and weathered rock resulting from the force

Soil Formation and Mass Movements - Weebly

mass wasting - Glendale Community Collegerafael.glendale.edu/ppal/Word files/MacConnell's Mass Wasting Note… · Mass wasting represents the downslope movement of material under

Mass Movements aka Landslides

LITHOSPHERE: MASS MOVEMENTS AICE Environmental Management

MASS MOVEMENTS, WIND, & GLACIERS mass movement = when gravity alone causes loose sediments and weathered rock to move downslope sediments and weathered

Soils & Mass Movements · Mass Movements •Mass Movement: The downslope movement of soil and weathered rock resulting from the force of gravity •All occur on slopes •Because

Chp14: Mass Wasting Mass Wasting (mass movement) -defined as the downslope movement of material under the influence of gravity -aided most by weathering

MASS MOVEMENTS, WIND, AND GLACIERS › earthscience › worksheets › ch8wsweb… · MASS MOVEMENTS, WIND, AND GLACIERS SECTION 8.1 Mass Movements In your textbook, read about mass

Engineering Geology Mass movements

Chap08 Mass Movements,Winds and Glaciers

Mass movements

MASS MOVEMENT - City College of San Francisco · 11/28/2012 1 MASS MOVEMENT Landslides Mass Movement Mass Movement: Movement of earth materials (bedrock, sediment, soil) downslope

Soils, Mass movements, and soil conservation

Mass Wasting. What is Mass Wasting? The downslope movement of slope material. Gravity is the key to mass wasting. Landslides are mass wasting

Submarine Mass Movements: Sedimentary Characterization and

Prentice Hall EARTH SCIENCE · The transfer of rock and soil downslope due to gravity is called mass movement. Among the factors that commonly trigger mass movements are saturation

Mass Movements Landslides - Weebly

8 Mass Movements, Wind,and Glaciers

Mass Movement (Mass Wasting) - Michigan State …michal76/classstudyguides/GEO 306 Environmental... · Mass Movement (Mass Wasting) -Downslope movement of regolith under the influence

Mass Wasting - Western Oregon Universitywou.edu/~brownk/ES105/ES105.2011.0228.MassWasting.9.pdf · Mass Wasting Erosion Chapter 23 Mass Wasting The downslope movement of rock, regolith,

#14 Mass Movements

CHAPTER 5.3 MASS MOVEMENTS

Environmental Geology Mass Wasting and Hillslope Processestaylors/g473/masswast.pdf2. Mass Wasting- mass movement of weathered rock materials downslope under the force of gravity:

Mass Wasting The downslope movement of rock and soil due to gravity

Lithosphere: Mass Movements

Tarbuck Lutgens - Springfield Public Schools · The transfer of rock and soil downslope due to gravity is called mass movement. Among the factors that commonly trigger mass movements