mass movements aka landslides

Mass MovementsMass Movementsakaaka

LandslidesLandslides

Def: movement of sediment Def: movement of sediment due to GRAVITYdue to GRAVITY..

http://www.youtube.com/watch?v=QdsxtCtX5nk&feature=player_detailpage

ROCKFALL

Rockfall- bouldersRockfall- boulders

ROCKSLIDE

I-40 North CarolinaI-40 North CarolinaNov. 2009Nov. 2009

►http://www.youtube.com/watch?v=ZVYGJYnJTi0

AVALANCHEAVALANCHE

► Fast movement of Fast movement of snowsnow

► Caused by a weak Caused by a weak layer of snow layer of snow underneath surfaceunderneath surface

► Usually in SpringUsually in Spring►http://www.youtube.

com/watch?v=B0RWLxOFGLY

Avalanche Danger In Colorado At 30 Year High, Says Expert; 6 Fatalities So Far This Season

Snowbird, UT Snowbird, UT Nov. 2011Nov. 2011

► Jamie Pierre, here performing an extreme jump, was killed while snowboarding near Gad Valley on

Sunday.

TellurideTelluride

http://www.nwac.us/media/http://www.nwac.us/media/uploads/documents/accidents/uploads/documents/accidents/

US_avalanche_fatalities_by_userUS_avalanche_fatalities_by_user_group_by_year_1997-2XXX.pdf_group_by_year_1997-2XXX.pdf

Mudflow/LaharMudflow/Lahar

►Mudflow- clay mixed with waterMudflow- clay mixed with water►Usually in spring- snowmeltUsually in spring- snowmelt

►Lahar- volcanic ash mixed with waterLahar- volcanic ash mixed with water

MudflowMudflowJava 2007Java 2007

http://www.youtube.com/watch?v=VMJiibdVYjE&feature=player_popout

►http://www.youtube.com/http://www.youtube.com/watch_popup?watch_popup?v=VMJiibdVYjE&vq=small#t=34v=VMJiibdVYjE&vq=small#t=34

Lahar

MT ST HELENS

SLUMPSLUMP►Saturation of water + Saturation of water + loss of friction causes loss of friction causes

soil soil belowbelow surface layer surface layer to drop downhill.to drop downhill.

►Surface stays intactSurface stays intact

CREEPCREEP

► SLOW movement of SLOW movement of soilsoil

► Causes tilting of Causes tilting of objectsobjects

► Usually soilUsually soil► Result of Result of

freeze/thawfreeze/thaw

CREEP

CreepCreep

SOLIFLUCTIONSOLIFLUCTION

► IN ARTIC CLIMATESIN ARTIC CLIMATES► In spring when top layer melts, moves In spring when top layer melts, moves

slowly over permafrostslowly over permafrost

ARE MASS MOVEMENTS ARE MASS MOVEMENTS WEATHERING OR WEATHERING OR EROSION?EROSION?

Factors influencing Mass Factors influencing Mass MovementMovement

► 1. Amount of moisture1. Amount of moisture More adds weight and makes slipperyMore adds weight and makes slippery

► 2. angle of slope2. angle of slope► 3. lack of vegetation3. lack of vegetation

Roots hold back movementRoots hold back movement► 4. rock type4. rock type

Sedimentary worstSedimentary worst► 5. Roundness of particle5. Roundness of particle

Rounder move fasterRounder move faster

Mass movementsMass movements

►Cost US $4 billion per yearCost US $4 billion per year

►http://landslides.usgs.gov/recent/http://landslides.usgs.gov/recent/index.php?year=2009&month=Octindex.php?year=2009&month=Oct

Landslide Causes?Landslide Causes?

►http://www.youtube.com/watch?http://www.youtube.com/watch?v=JrV4uCVwmfkv=JrV4uCVwmfk

Laguna Beach 2005Laguna Beach 2005

Philippines Feb. 2006Philippines Feb. 20061800 dead1800 dead

Sleeping bear dunes 1995Sleeping bear dunes 1995

Prevention methodsPrevention methods

► Fences/wallsFences/walls Temporary fixTemporary fix Gravity will win Gravity will win

eventually!eventually!

Prevention methodsPrevention methods

► Leave enough Leave enough space!space!

Prevention methodsPrevention methods

► Leave enough Leave enough space!space!

Prevention methodsPrevention methods

► Plant vegetationPlant vegetation► Roots act as Roots act as

anchorsanchors

Prevention methodsPrevention methods

► Provide good drainage- excellent way!Provide good drainage- excellent way!

Prevention methodsPrevention methods

► Provide good Provide good drainagedrainage