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Landslides

By: Kimberly Alcala

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Definition

Landslides are rock, earth, and/or debrisflowing or sliding down slopes due togravity.

The downward sliding of a relatively dry

mass of earth and rock.

the falling or sliding of a mass of soil,

detritus, or rock on or from a steep slope.

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CausesHeavy rains

Earthquakes

Volcano eruptions

Floods

Grading

Terrain Cutting

Droughts

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Air

Confined by falling rock debris,

air may act as a cushion to

reduce the friction between thesliding material and the

underlying rock or ground.

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Gravity

Gravity provides the energy to

displace the soil and bedrock, but

other factors contribute to anincrease in stress and decrease in

strength. A stress tends to make part

of a block material slide blockmaterial slide with respect to an

adjoining part.

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Vibrations

Vibrations from blasting, heavy traffic

and earthquakes also can contribute toshear stress and precipitate slides.

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Speed

Landslides travel at least over than 260

feet per second

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TypesRockfalls- large chunks of rock that tumble down acliff or steep slopes

Lahars- ash from a volcano mixes with water, to forma thick river of mud

Earthflows- contain less water and flow more slowly;move shorter distances

Slope Failure- involve one block or a series of slumpblocks

Slump- larges masses move downward and outwarddue to a gravity pull

Debris Slides- consist of moving masses of mud, soil,

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Hotspots

Anywhere with steep slopes andweathering

High mountain ranges, sheer cliffs, andsteep sided river valleys

Where volcanoes erupt and alongcoasts

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Effects

Bury entire villages that are at thebottom of the mountain range

Close roads

Rapidly moving water and debris cancause trauma

Broken gas, electric, water, and sewagelines can break

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EffectsLandslides also sweep up trees, cars,

and buildings

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Traffic Stops

Landslides can cause a headache for many

travelers on the road

Landslides occur on hills near roads quite

often causing bad traffic

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Pictures

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Safe Spots From Landslides

Stay on hard bedrock that has not beenmoved lately or in the past

Stay on relatively flat-lying areas far fromslopes or river banks

Stay at the top of ridges, away from thetop of slopes

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SUMMARYA landslide or landslip is a geoligcal phenomenon

which includes a wide range of groundmovements, such as rockfalls, deep failure of

slopes and shallow debris flows, which can occur

in offshore, coastal and onshore environments.

Although the action of gravity is the primary drivingforce for a landslide to occur, there are other

contributing factors affecting the original slope

stability.Typically, pre-conditional factors build upspecific sub-surface conditions that make the

area/slope prone to failure, whereas the actual

landslide often requires a trigger before being

released.

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REFLECTION

Landslides occur in many geographicregions, in response to a wide variety of

conditions and processes, and result in

substantial damages. Although some

landslides are due to human activity, othersare unavoidable natural processes that

occur on apparently undisturbed land, and

this differing causality may require attentionby a number of different regulating

authorities.