NAME       : ERY IRFIYANI
CLASS      : XII RPL 2
NO             : 07
 
 
 
A.  Understanding Landslide

Landslides or in English is called Landslide , slope -forming material is in the form of
 displacement of rock , debris material , soil , or a mixture of the material , move down or off the slopes . The occurrence of landslides can be explained as follows : the water soak into the ground will add weight to the ground . If water penetrates the soil acts as a waterproof slip plane , the ground became slippery and soil weathering on it will move to follow the slope and off the slopes .


B. Types of Landslide

There are 6 types of landslides , namely : translational landslides , avalanches rotation ,
movement of blocks , rubble stone , rayapan soil and debris flow material .
 Translational and rotational landslide types most common in Indonesia. Whereas most avalanches claimed the lives of humans is debris flow material .

1 . Translation avalanche
Air- translational landslide is a mass movement of soil and rock in the field of flat or menggelombang shaped slip ramps .
2 . avalanches Rotation
Rotational landslide is moving its mass of soil and rock on the slip plane is concave .
3 . Block movement
Movement is the movement of rock blocks that move in the field of flat -shaped slip . Avalanches are also called rock avalanches translational block
4 . Stone ruins
Sejum rock slides occur when the one large rock or other material moving downwards by free fall . Generally occur on steep slopes up dangling especially in coastal areas . Large boulders that fall can cause severe damage .
5 . Land Rayapan
Rayapan Land is kind of slow-moving landslides . Type of soil in the form of coarse and fine grain . Type of landslide is almost unrecognizable. After a long time this rayapan landslide types can lead to telephone poles , trees , or the downward sloping .
6 . Debris flow material
This type of landslide occurs when land masses move driven by water . Flow rate depends on the slope, the volume and pressure of water , and type of material . Movements occur along the valley and can reach hundreds of meters away . In some places can be up to thousands of meters such as in watershed areas around the volcano . This land can stream pretty much killed .
 
 
 
 
C. Common symptoms Landslide

Common symptoms that usually occur before the occurrence of landslides are :
The emergence of the cracks in the slope that is parallel to the direction of the cliff .
 It usually occurs after rain .
 The emergence of new springs suddenly .
 fragile cliffs and gravel began to fall .
 

 
D. The occurrence of Factors Contributing to Landslides

In principle landslide occurs when the driving force on slopes greater than retaining style.
Anchoring force is generally influenced by the strength of rock and soil density . While the driving force is influenced by the magnitude of the slope angle , water , and heavy loads of rock soil types .
 
a.rain
Threat of landslides usually begins in November due to the increased intensity of rainfall . Long dry season would lead to the evaporation of water in the ground in large numbers . It resulted in the appearance of pores or voids ground cracks occurred and the breaking up of the surface .
When it rains , water will infiltrate into the ground with a crack so quickly re-inflated . At the beginning of the rainy season , high rainfall intensity is usually true , so that the water content in the soil to become saturated in a short time .
Heavy rains early in the season can cause landslides , because the water broke through the soil will enter and accumulate in the bottom of the slope , causing lateral movement . If there are trees on the surface , landslides can be prevented because the water will be absorbed by plants . Plant roots bind the soil will also work .
 
b . steep slopes
Steep slopes or cliffs which will increase the driving force . Steep slopes formed by the erosion of river water , spring water , sea water , and wind . Most of the slope angle is 180 mudslides when the slope was steep and field ends flat erodible soils .
 
 
c. Soil is less dense and thick
Type of soil is less dense clay or clay with a thickness of more than 2.5 m and slope angle is more than 220 . This type of soil has the potential for the occurrence of landslides , especially when it was raining . In addition it is highly susceptible to soil movement due to soft soil exposed to water and broke when it was too hot .
 
d . Rocks are less powerful
Sedimentary rocks and volcanic rocks and sand -sized sediment mixture of gravel , sand , and clay are generally less powerful . The rocks will easily be ground when experiencing the process of weathering and generally prone to landslides when found on steep slopes .

 
e . Type of land planning
Many landslides occurred in the area of ​​governance paddy fields , cultivation , and a puddle of water on steep slopes . In the paddy fields is less strong roots to bind the soil and make the soil grains become soft and saturated with water slide so easily happen . As for the area of ​​cultivation the cause is due to the tree roots can not penetrate the field of landslide and avalanches generally occur in the area long .
 
f . vibration
Vibrations that occur are usually caused by earthquakes , explosions , vibration machine , vibration and vehicle traffic . Its consequences are ground , the road , floor , and walls being cracked .
 
g . Shrinkage of the lake water level or dam
Susutnya due to rapid water level in the lake then retaining style slope becomes lost , the tilt angle of the reservoir 220 easy going avalanches and land subsidence is usually followed by cracks .
 
h . Any additional burden
Any additional expenses such as building loads on the slope , and vehicle driving style will increase the occurrence of landslides , especially around the bend in the road in the valley area . The result is often a decrease in soil and cracks him in the direction of the valley .
 
i . Abrasion / erosion
Water erosion is mostly done by the river in the direction of the cliff . In addition to deforestation around the bend of the river , would be a steep cliff .
 
j . The existence of material deposits on the cliff
To develop and expand the residential land is generally done cutting cliffs and valleys hoarding . Soil deposits on the valley has not been perfect as the original soil compacted thereunder . So if the rain will decrease the soil , followed by soil cracks .
 
 
k. Former long avalanche
Long avalanches generally occur during and after the deposition of volcanic material on relatively steep slopes or at the time of or after the occurrence of faults the earth's crust . The former has an old avalanche characteristics :
Ø  The long steep cliffs curved shape of a horseshoe .
Ø  Commonly encountered springs , relatively thick trees because the soil loose and fertile .
Ø  Regional landslide upper bodies are generally relatively gentle .
Ø  Encountered small avalanches , especially in the valley cliffs .
Ø  Encountered relatively steep cliffs , a former small avalanche on the old landslide .
Ø  Encountered groove valley and the ridge is found cracks and small avalanches .
Ø  wide enough avalanche this long .
 
 
 l. The existence of a discontinuity field ( field is not continuous )
This field is not continuous characterized by :
Ø  Field perlapisan rock
Ø   Field contact between the overburden bedrock
Ø   Field contact between the cracked rocks with rock solid .
Ø   Field contact between the rocks that can pass water with rocks that do not pass water ( water-resistant ) .
Ø   Field contact between the soft soil with solid ground .
Ø   these areas is weak areas and can serve as a glide plane landslides .
 
m . deforestation
Landslides are generally a lot going on in a relatively barren area where ground water is very less binding .
 
n . Waste disposal area
The use of low soil layer for landfills in large quantities can cause landslides especially coupled with the rain, as happened in Leuwigajah Waste Landfill in Cimahi . This disaster left an estimated 120 more people died .
 
 
 
 
 
E. Landslide -prone areas

            At least 918 landslide-prone locations in Indonesia. Each year the losses incurred due to landslides around Rp 800 billion , while the soul is endangered about 1 million .
Landslide -prone areas that have :
v  Central Java 327 Locations
v  West Java 276 Locations
v   West Sumatra 100 Locations
v   North Sumatra 53 Locations
v   Yogyakarta 30 Locations
v   West Kalimantan 23 Locations
v   The rest are scattered in NTT , Riau , East Kalimantan , Bali and East Java .



F. Landslide Disaster Mitigation Phases  Mapping
 
Presenting visual information about the vulnerability of geological disasters in the
 region , as input to the community and or the district / city and province as a baseline for the development of the region do to avoid disaster .
 investigation.
Study the causes and effects of a disaster that can be used in disaster planning and regional development plans .
 Inspection.
Investigated during and after a disaster occurs , so as to know the cause and how to overcome them .
Monitoring carried out in disaster-prone areas , the economically strategic areas and services , in order to know at an early level of danger , by the users and people living in the area .
 Socialization.
Provide insight to the Provincial / District / City or the general public , about the natural disaster that caused landslides and ditimbulkannnya . Socialization is done in various ways , among others , sending posters , booklets and leaflets, or can also directly to the public and government officials.
            Inspection landslide
Aims at studying the causes , the occurrence , disaster conditions and procedures for disaster management in an area that was devastated by landslides .
 


 
G. Measures Can Do During and After Landslide

1 . Emergency Response
What to do in the emergency response was immediate victim rescue and relief so that the victim does not grow . There are several things to consider , among other things :
·         terrain conditions
·          disaster condition
·          Equipment
·          disaster information
 
2 . rehabilitation
Victim recovery efforts and infrastructure , including social, economic , and transportation facilities . In addition it also studied the development of landslides and soil erosion control techniques that do not develop and determination relocation landslide victims when landslides are difficult to control .

3 . reconstruction
Strengthening infrastructure buildings in areas prone to landslides are not a major consideration for mitigating damage caused by landslides , as vulnerability to buildings built in landslide lane almost 100 % .