Topic of the day(Landslides)

What?

1.Falling down of land or mountain along the slope under the influence of gravity.

Geo Distribution in India

1.Himalayan area---HP, Jnk, Uttrakhand

2.Western Ghats

3.Arakom yoma belt of northeast

4.meghalya

5.nilgiri

Difference between himalayan and western area landslide

1.Himalayan-tectonically unstable

2.himalaya-huge landslides, Western-slides confine to over burden without effecting bedrocks beneath

3.Himalaya-slides, Western-debris flow

4.himalaya-density of population is less therefore as compare to plateau region

Example

1.Malpa landslides of 1998-entire village was buried by huge landslide

Reason---when stable slope condition changes to unstable slope conditions

Natural-

1.Gravity

2.Unstable landmass

3.Earthquake

4.Flood

5.Volcanic

6.Groundwater pressure

7.erosion by rivers or ocean waves

Human

1.Unregulated construction of highways and other infrastructure

2.overgrazing

3.Tourism

4.Mining and blasting in mountain areas

5.removing vegetation

6.deforestation

7.cultivation

Types

1.debris flow-slope material saturated with water and move down 

2.Earth flow---slower than debris

3.debris landslides

4.movement-faster than debris landslides

5.shallow landslides-

6.deep seates landslide-

Ways

Reducing manmade reasons

1.Planned construction

2.regulating grazing

3.afforestation

4.regulated tourism

5.proper policies and better coordination between institutions and user agencies

6.micro-zonation to regulate settlement in hazard prone area

7.non-interference with natural waterchannel

8.construction of retaining wall against steep slope

9.strengthing of weak area with grouting

TechnologiCal ways

6.technological like reducing ground water level,changing the geometry of hillsides etc

Managing natural reasons

1.mapping of eq zone

2.making people aware regarding what to do during EQ effected landslide etc

Institutions arrangement

1.Geological survey of India--nodal agency in handling landslides