causes for landslides

1. rain 
2. ground water 
3. gravity 
4. quakes & severe storms 
5. human neglegence 

• speeds @ 40 mph 
• more often due to natural forces 

a pile of sediment that was formed when U.S was under water and due to tectonic reasons the entire thing lifted above sea level.

• Gravitational movement of material downslope
• Water may be present, but as a passive agent
•  Gravity is the transport process and is only cause of mass wasting.

o   presence of water – hurricanes make slopes saturated

o   geology – material like in California that is unstable

o   steepness of slope

Stress: pulls material down the slope (weight of material & steepness of slope) 

Strength: holds material together (measure of internal friction) 

§  35 degrees – fine sand

§  40 degree – course sand

§  45 degrees – pebbles 

How does angle of repose change? 

(5) 

o   Saturation of material with water

o   Earthquake vibrations

o   Expansion and contraction of regolith

o   Undercutting of slopes by streams, waves, and US!  - so we can make roads.

(EX: In California- developers come to a slope and dig out a side, pile the sediment farther out to make it flatter and it causes dangerous situation) 

o   Oversteepening: filling past the angle of repose. 

o   Good: as long as sediment grains are touching each other

o   Bad: when no longer touching and sediment grains are separated  

What Does Vegetation Do To Slopes? 

o   Good: hold sediment and land together  

o   Bad: have to pick the right kind of vegetation.. water loving vegetation pulls the water out of the soil, removing the water the holds the soil together.

Creep 

(type of mass wasting) 

§  A very slow down slope movement of soil and rock

§  EX: Grand Canyon – exposing the roots in trees. 

§  Solifluction: Creep and permafrost 

slump 

(type of mass wasting) 

§  Moderately fast.

§  Occurs along a curved rupture surface and the rest of the material that is moving stays in tact. 

§  Problem for power lines – they could eventually snap

debris flow 

(type of mass wasting) 

§  Rapid mix of soil, mud, rock, water, maybe ice.

§  Rain infiltrates into the sub surface and just sits there.  –causes a debris fan

rock fall 

(type of mass wasting) 

§  Free fall from very steep cliffs.

§  Rock slide is slightly slower than a rock fall but both very fast.

§  Very dry.  

two ways geologists classify mass wasting                             

                              1.     How quickly they occur

                              2.     How much water is present 

so much water that the materials behave like a liquid and float

ways to prevent mass wasting

(5) 

o   Revegetation: plant trees again- increases angle of repose – increases slopes stability

o   Redistribute Mass: look at places that are too heavy and take that away and add to places that don’t have enough support

o   Lower Water Table: clay absorbs water

o   Terracing: remove load, catch debris ( like putting steps in the side of the hill)

o   Relocating River Channel: reroute the river channel where it is causing erosion 

more ways to prevent mass wasting 

(4) 

o   Rip- Rap: absorbs wave energy. (Energy from wave is absorbed by possibly tires, hay bails, cement blocks, etc.)

o   Retaining Wall: on or some distance away from the slope (Causes the sediment or pavement) 

o   Bolting: Rock bolts – structurally sound rock that could potentially hurt people.  It is drilled down into the sub-surfaces.  

o   Avalanche Shed: steel shed that the avalanche passes over.  

no slope involved 

-- we withdrawal oil, or gas, or water so sediment collapses 

is subsidence reversible? 

How so? (3 ways) 

o   Inject water into the ground

o   Ground doesn’t rebound

o   Strops sinking further 

Subsidence 

any extra terrestrial material that strikes earth 

(earth was created by meteorite impacts) 

what happens when meteorite enters earth's atmosphere?

(2)  

1. encounters friction 
2. causes Ionization --BURNS

• “dirty snowball”
• bright object with long wispy tail
•  always points away from the sun.
•  some rocks, some snow, loosely held together. 
• travel around and spray out fragments 
• 200 pass earth 
• appear out of nowhere

** the cause for concern** 

parts of a comet 

(4) 

o   Ionized gas tail volatilized icey material from nucleus.

o   Coma (bright, diffuse halo around nucleus)

o   Dust tail (ionized rock part)

o   Nucleus (ice) 

Evidence comets are from far outer reaches of solar system  

(5) 

·      icy composition

·      highly elliptical orbit

·      don’t trace within Sun’s equatorial plane

·      very loosely held together

·      anything greater that 1 diameter can leave an ”impact crater” 

 Why Earth doesn’t show craters like the moon does? 

(4) 

o   We have a hydrosphere (weathering and erosion which makes it indistinguishable)

o   Atmosphere burns things up

o   70% water. 

o   Plate tectonics recycles the plates 

The moon is a piece of earth created by a meteorite strike on earth. 

For a crater to survive on earth

(3) 

MUST BE: 

o   Very large

o   Very recent

o   On very stable geographic environment. 

what would the effects of a meteorite impact be? 

(5) 

1. Huge Tsunami: impact if in water  
2. Massive rising in temps & global wild fires: huge radioation of fireball entering atmosphere 
3. Global darkness: dust in atmosphere/ blanket of ash/ crop failure/ food chain collapse 
4. Cold: darkness = intense cold 
5. Heat:water vapor into the atmosphere/ dust settles: intense global warming
6. Acid Rain

• gas increase 
• coincident with burning of fossil fuels 

** humans permanently altered compostion of atmosphere 

Human Inputs

(5) 

o   CO2 (carbon dioxide)

o   CFCs (cholofloral Carbons)

o   All these gases are rising

o   CH4 (methane) much lower than CO2

o   N2O (nitrogen compounds – primarily from fertilizers) 

·      Coil, oil, gas

·      Buried remains of organizations

·      Modern society dependent

·      Coal 

§  Strip mining (rip the top of the earth off destroying ecosystems) 

§  Acid rain

§  Large volumes of ash generated

§  Global warming 

o   Hydrocarbons – CH4 chains

o   Microscopic algae & plants in oceans and large lakes

o   Rapidly buried, no decomposition.

 (Earthquakes trap oil and gas / Salt flats flow upward and bend the sediments upward and then combines with shale -- causing the trapping)  

o   Subsidence –land sinking

o   Acid rain

o   Global warming 

 The Green House Effect: 

§  Incoming solar radiation

§  Reflected by clouds dust and earth’s surface

§  Bounce off of particles and create heat 

§  Burning fossil fuels

§  That part of the green house effect that we are causing

§  We are putting these gases into the atmosphere

·      What is the difference between global climate change and the greenhouse effect? 

Environmental impacts of Global Warming 

(7) 

·      Global precipitation changes

·      Vegetation changes

·      Glacier melting

·      Sea level rise

·      Reduce sea ice

·      Thawing of the ground

·      Organic matter decomposition

Ecological Implications of Global Warming  

(3) 

·      Higher latitudes

·      Higher elevations

·      Loss of biodiversity 

Global Warming Solution

(8) 

·      Cut fossil fuel use

·      Improve energy efficiency

·      Shift to renewable energy resources.

·      Reduce deforestation

·      Use sustainable agriculture

·      Slow population growth

·      Clean up

·      Remove CO2 from smokestack and vehicle emissions