Earth Flow

K. Diyes B. Amarathunga11/SS/005

Geology

Faculty Of GeomaticsSabaragamuwa University Of Sri Lanka

Mass Wasting• Mass wasting is the geomorphic process by

which soil, sand, regolith, and rock move downslope typically as a mass, largely under the force of gravity..

• Mass wasting, also known as slope movement or mass movement.

Koslanda Disaster

Mass Wasting

Creeps Landslides Flows Slump Falls

Flows• ‘Movement of soil and regolith that more

resemble fluid behaviour is called’ as a flow.

• Flow includes : Rock Avalanches Mudflows Debris flows Earth flow Sturzstroms

• Earthflows are one of the gentler kinds of landslide.

• It consist of soil and weathered rock—earth—and they move as a fluid—flow.

• An earthflow may affect as few as several square meters or up to several hectares.

Earth Flow

•Earthflows often begin as slumps.

•Usually, like slumps, they do not move very fast.

Road cut caused Earthflow

Reasons for Earth Flows..?

• Clay, fine sand and silt, and fine- grained pyroclastic materials are susceptible to earthflows .

• When the ground materials become saturated with enough Water, they will start flowing.

• Because of the dependency on water content for the velocity of the flow, it can take minutes or years for the materials to move down the slope.

• Most commonly heavy rains

• Volcanic eruptions• Earthquakes

La Conchita

1995 earthflow

Reasons for Earth Flows..?

How Earth Flows can be reduced..?

• Afforestation A place can be prepared as a forest where there was no forest.

How Earth Flows can be reduced..?• Re-forestation

Moderating the lands which are in a risk of Earth Flows.

How Earth Flows can be reduced..?

• Terracing steps on slopesMaking a land which is at a risk with Earth Flow, as a steps to avoid the flowing.

• Covering the landslide with an impermeable membrane.

• Directing surface water away from the landslide.

• Draining ground water away from the landslide

• Minimizing surface irrigation.

How Earth Flows can be reduced..?

Earth flow

• ..\Earthflow and Landslide in Italy.mp4

Thank You..