Related Geological Hazards

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related geological hazards

Approximately 55 earthquakes a day

20,000 earthquakes per year

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Definition, Types, Factors, Causes & Signs

RAinfall-induced landslides

01

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LANDSLIDE

What is it?

definition

- United States Geological Survey (USGS)

A down-slope movement of soil, rock, and organic materials under the effects of gravity and also the landform of that results from such movement.

Categorized based on the type of materials and movement involved

Major types of landslides

FALL

Begins when materials on cliffs or steep slopes lose support or becomes fractured from the main rock.

TYPES OF LANDSLIDES

TOPPLE

Happens when a block of material is detached from a steep slope such as cliff and moves forward and downward around a point of axis

TYPES OF LANDSLIDES

SLIDE

Occurs when a detached mass of materials such as rocks move along a downward sloping surface.

TYPES OF LANDSLIDES

Mass that slides down and outward along a downward sloping surface.

Translational landslide

Rotational landslide or slump

Displaced mass is moving along a concave surface.

TYPES OF SLIDE

FLOWS

Occurs when materials from gentle slopes are detached and flow like a viscous liquid along a surface.

TYPES OF LANDSLIDES

- Volcanic mudflow, a type of debris flow

• Lahar Flow

Debris Flow

A rapid movement of slurry (mudslide) is formed from water that combines materials such as rocks and soil sometimes.

TYPES OF FLOWS

Debris Avalanche

Occurs from sudden collapse of unstable slopes and the fragmented debris rapidly moves downwards along the slope.

TYPES OF FLOWS

Earth Flow

When the flow has a high amount of silt and clay.

TYPES OF FLOWS

SPREADS

Occurs when the mass of soil or rocks extends or spread laterally.

TYPES OF LANDSLIDES

FActors THAT INFLUENCE LANDSLIDE DEVELOPMENT

Human activities

Human

Shape of land and its slope

Morphological

Geological

Weathered and Fractured materials

FACTORS:

Causes of rainfall-induced landslides

Volcanic activity

Seismic

Water (Rainfall)

CAUSES:

Definition, Formation, & Types

sinkholes

02

Described as a downward movement of earth's crust towards its gravity.

WHAT IS A SINKHOLE?

What is it?

definition

A type of ground subsidence that occurs because the rock below is either limestone, carbonated rocks, or salt bed that was continuously penetrated by circulating groundwater for a long time.

SINKHOLE

FORMATION OF SINKHOLES

Karst Terrains

A place geologists call where sinkholes form.

FORMATION:

types OF SINKHOLES

DISSOLUTION SINKHOLES

Forms from dissolution of the limestone or dolomite by water or acid.

TYPES OF SINKHOLES:

COVER-SUBSIDENCE SINKHOLES

Developed in areas where the covering sediments contain sand and permeable.

TYPES OF SINKHOLES:

COVER-COLLAPSE SINKHOLES

FDeveloped in areas where the covering sediments contain a significant amount of clay.

TYPES OF SINKHOLES:

Definition, Causes, Effects, & Tips

ground subsidence

03

HUMAN-INDUCED SINKHOLES

Associated with human activities such as ground water pumping, construction, and land development practices.

TYPES OF SINKHOLES:

What is it?

definition

United States Geological Survey (USGS), defined ground subsidence as the loss of surface elevation due to the removal of subsurface support.

GROUND SUBSIDENCE

some CAUSES OF ground subsidence

COMPACTION

of soil due to natural or man-induced processes will displace air spaces, making the soil impenetrable and more susceptible to subsidence.

SOME CAUSES:

SUBTERRENIAN MINING

or underground mining activities including extraction of fluid materials displaces numerous materials under the surface

SOME CAUSES:

EFFECTS OF GROUND SUBSIDENCE

Ground subsidence can impact agricultural lands, industrial processes, and infrastracture.

EFFECTS:

some tips to reduce occurence of ground subsidence

• Finding alternative sources to groundwater
• Avoiding building infrastracture in certain distances near land fissures;
• Routing drainage away from fissures; and
• Prohibiting residential zones in or near fissure areas or types of ground that have subsidence susceptibility.

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