Slope Movement

50 %
50 %
Information about Slope Movement

Published on November 19, 2008

Author: maliadamit

Source: slideshare.net

Description

Mass movement (Paper 1)

SLOPE CURRENTLY ACTIVE LANDSLIDE IN PAKISTAN Lots of angular rock fragments lying at foot of slope-talus. EVIDENCES: (2) Bare rock exposed to weathering. (3) Absence of vegetation.

Lots of angular rock fragments

lying at foot of slope-talus.

WHY ARE SLOPES IMPORTANT? Wyllie Vineyard, California Rock Climbing skiing Hang gliding Mountain Biking Rice terrace in Philippines

MAJOR SLOPE PROCESSES (I) ROCK FALLS: Rapid movement occurs on steep slopes. Rock fragments/slabs of rock suddenly detached and fall at base of slope. This is due to gradual processes such as freeze-thaw/earthquakes. The angular debris collects at base of slope to form scree / talus.

Rapid movement occurs on steep slopes.

Rock fragments/slabs of rock suddenly detached and fall at base of slope.

This is due to gradual processes such as freeze-thaw/earthquakes.

The angular debris collects at base of slope to form scree / talus.

MAJOR SLOPE PROCESSES (II) LANDSLIDE : Movement takes place along a flat/planar slide plane. It commonly occur along bedding planes when underlying bed is impermeable,lead to a high moisture content that lubricate the slide surface. Landslides are very rapid and cause damage & loss of life.

Movement takes place along a flat/planar slide plane.

It commonly occur along bedding planes when underlying bed is impermeable,lead to a high moisture content that lubricate the slide surface.

Landslides are very rapid and cause damage & loss of life.

(III) ROTATIONAL SLIP/LANDSLIP. It differs from landslide in that the slide plane is concave in shape. It causes rotational movement. Common in weak rock such as clay. Most common in UK. MAJOR SLOPE PROCESSES head scarp Curved Slide plane foot toe

(III) ROTATIONAL SLIP/LANDSLIP.

It differs from landslide in that the slide

plane is concave in shape.

It causes rotational movement.

Common in weak rock such as clay.

Most common in UK.

(IV) MUDFLOW When soil/weak rock such as clay or volcanic ash become saturated, it begin to flow downhill. This flow can be slow but mostly rapid depend on water content. Mudflows from volcanic summits combine with ash to form deadly flows called lahar. Lahar caused loss of life & damage property e.g. eruptions of Mt. Pinatubo, Philippines (1991). MAJOR SLOPE PROCESSES

(IV) MUDFLOW

When soil/weak rock such as clay or volcanic ash become saturated, it begin to flow downhill.

This flow can be slow but mostly rapid depend on water content.

Mudflows from volcanic summits combine with ash to form deadly flows called lahar.

Lahar caused loss of life & damage property e.g. eruptions of Mt. Pinatubo, Philippines (1991).

Solifuction is the slow downhill flow of saturated soil. Common process in periglacial environments. Seasonal thawing of uppermost layer provide enough water to enable flow to occur. Gelifluction refers to solifuction takes place on top of frozen ground. MAJOR SLOPE PROCESSES (V) SOLIFUCTION

Solifuction is the slow downhill flow of saturated soil.

Common process in periglacial environments.

Seasonal thawing of uppermost layer provide enough water to enable flow to occur.

Gelifluction refers to solifuction takes place on top of frozen ground.

(VI) SOIL CREEP It involves a heavy process where individual particles rise & fall respond to expansion & contraction. This is due to wetting & drying /freeze thaw action. 3. A very slow process, particularly on clay slope. 4. Terracettes on grassy slopes result from soil creep. MAJOR SLOPE PROCESSES

(VI) SOIL CREEP

It involves a heavy process where individual particles rise & fall respond to expansion & contraction.

This is due to wetting & drying /freeze thaw action.

3. A very slow process, particularly on clay slope.

4. Terracettes on grassy slopes result from soil creep.

FACTORS AFFECT SLOPE PROCESSES Physical (i) Rock type : Tougher rock such as igneous & metamorphic rocks (steep) while sand and gravel (gentle slope). (ii) Geological structure : Rock slabs detached along joints and bedding planes promote rockfalls & landslides. (iii) Permeable & porosity : An impermeable rock will be liable to surface water flow, deep gullies may be form. (iv) Climate : affect weathering type; physical weathering such as frost shattering produce angular, bare rock surface and chemical weathering tend to disolve and produce fine clay producing more rounded slopes. (v) Tectonic activity: Earthquakes may also trigger slope failure.

Physical

(i) Rock type : Tougher rock such as igneous & metamorphic rocks

(steep) while sand and gravel (gentle slope).

(ii) Geological structure : Rock slabs detached along joints and bedding

planes promote rockfalls & landslides.

(iii) Permeable & porosity : An impermeable rock will be liable to surface water flow, deep

gullies may be form.

(iv) Climate : affect weathering type; physical weathering such as frost shattering

produce angular, bare rock surface and chemical weathering tend to disolve

and produce fine clay producing more rounded slopes.

(v) Tectonic activity: Earthquakes may also trigger slope failure.

( B) Human factors: Vegetation : If a slope is forested/covered with bushes & grass it is likely to be active. Vegetation help to protect slope from direct effects of rainfall & help bind rock and soil particles. (ii) Basal excavation : it takes place in the form of river undercutting of a slope/sea cutting a notch in a cliffline. Human activity such as road construction have same effect. This lead to a steep slope, make it unstable. (iii) Human activities : people alter slopes by mining & quarrying, road construction, housing estates and terracing land for farming. Deforestation can cause soil erosion. FACTORS AFFECT SLOPE PROCESSES

( B) Human factors:

Vegetation : If a slope is forested/covered with bushes & grass it is likely to be active. Vegetation help to protect slope from direct effects of rainfall & help bind rock and soil particles.

(ii) Basal excavation : it takes place in the form of river undercutting of a slope/sea cutting a notch in a cliffline. Human activity such as road construction have same effect. This lead to a steep slope, make it unstable.

(iii) Human activities : people alter slopes by mining & quarrying, road construction, housing estates and terracing land for farming. Deforestation can cause soil erosion.

Several ways to make a slope more stable: Plant vegetation to bind soil together & intercept rainfall. Improve drainage to prevent slope saturated & to stop lines of weakness for e.g. bedding panes becoming lubricated. Use wire nets & metal stakes to hold a slope together Reduce gradient by adding material to the base of a slope. Stable slopes.

Several ways to make a slope more stable:

Plant vegetation to bind soil together & intercept rainfall.

Improve drainage to prevent slope saturated & to stop lines of weakness for e.g. bedding panes becoming lubricated.

Use wire nets & metal stakes to hold a slope together

Reduce gradient by adding material to the base of a slope.

Add a comment

Related presentations

Related pages

Mass wasting - Wikipedia, the free encyclopedia

Mass wasting, also known as slope movement or mass movement, is the geomorphic process by which soil, sand, regolith, and rock move downslope typically as ...
Read more

SLOPE MOVEMENT PROCESSES AND CHARACTERISTICS

1.1 SLOPE MOVEMENT TYPES AND PROCESSES The mechanics and rates of slope movement are controlled by many factors: slope gradients, overburden depth ...
Read more

slope movement - Deutsch-Übersetzung – Linguee Wörterbuch

Viele übersetzte Beispielsätze mit "slope movement" – Deutsch-Englisch Wörterbuch und Suchmaschine für Millionen von Deutsch-Übersetzungen.
Read more

Slope Stability, Triggering Events, Mass Movement Hazards

EENS 3050: Natural Disasters: Tulane University: Prof. Stephen A. Nelson: Slope Stability, Triggering Events, Mass Movement Hazards
Read more

dict.cc Wörterbuch :: slope movement :: Deutsch-Englisch ...

Englisch-Deutsch-Übersetzung für slope movement im Online-Wörterbuch dict.cc (Deutschwörterbuch).
Read more

dict.cc | slope movements | Wörterbuch Englisch-Deutsch

Übersetzung für slope movements im Englisch-Deutsch-Wörterbuch dict.cc.
Read more

creep | slope movement | Britannica.com

Creep, creep G310stu in geology, slow downslope movement of particles that occurs on every slope covered with loose, weathered material. Even soil covered ...
Read more

Geologic Monitoring - nature.nps.gov » Explore Nature

What are slope movements? Slope movements refer to the downslope transfer of soil, regolith and rock under the influence of gravity. Slope movements may ...
Read more

mass movement | geology | Britannica.com

Mass movement, also called Mass Wasting, Evidence of mass wasting Mark A. Wilson (Department of Geology, The College of Wooster) bulk movements of soil and ...
Read more