Geomorphology Flashcards by Grace Ly

What is mass wasting/movement?

Gravitational downslope movement of rock and debris.

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What is slope stability?

Balance between shear strength (resistance) and shear stress (driving force).

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What are the components of shear strength?

Frictional characteristics (angle of friction/repose) * Effective normal stress (perpendicular stress) * Cohesion (internal bonding)

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What does the Coulomb-Terzaghi equation quantify?

Slope stability from shear strength components.

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What are the driving forces affecting slope stability?

Gravity * Material weight * Moisture * Slope angle * Shape/size of particles

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What are the resisting forces in slope stability?

Friction * Cohesion * Frictional strength

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How does pore water pressure affect slope stability?

It reduces effective normal stress, weakening the slope.

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What is the ‘Goldilocks zone’ of moisture?

The moisture level that produces the strongest slope; too dry or too wet weakens it.

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What are the main types of mass movement?

Falls * Slides * Flows * Creep

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What characterizes falls in mass movement?

Airborne material (rockfall).

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What distinguishes avalanches from falls?

Avalanches involve tumbling material, sometimes airborne (snow/debris).

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What defines landslides?

Cohesive/semi-cohesive materials, possibly moist.

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What are the types of landslides?

Translational (flat plane) * Rotational (curved surface)

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What is a significant case study of a landslide?

Aoraki/Mt Cook landslide (1991) - huge volume, high speed, no clear trigger.

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What are flows in mass movement?

High water content, fast, laminar movement.

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What is the case study for debris flows?

California 2010 debris flows post-wildfire.

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What causes creep in mass movement?

Slow soil/debris movement caused by freeze-thaw, wetting-drying cycles.

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What human activities destabilize slopes?

Deforestation * Overgrazing * Poor drainage * Construction

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What is sediment?

Broken rock fragments from weathering, erosion, transported by water, ice, wind.

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What characteristics define sediment?

Size (Φ scale, Wentworth scale) * Shape * Sorting * Skewness * Kurtosis * Color * Lithology

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What does roundedness of sediment indicate?

Transport history.

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What does sediment tell us about environmental conditions?

History of transport distance and conditions.

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What is the Hjulström Diagram used for?

Shows erosion, transport, deposition zones.

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What are the types of sediment?

Clastic (fragments) * Biological (shells, peat) * Chemical (precipitated minerals like calcite, gypsum, halite)

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What are the sedimentary environments?

* Continental (rivers, glaciers, deserts) * Coastal/Marine (abyssal plains, estuaries, beaches)

What initiates channel erosion?

Concentrated flow erodes soil/rock resistance.

What are the scales of erosion?

* Raindrop * Sheetwash * Rills * Gullies * Channels

What drives stream flow?

Gravity, resisted by friction.

Where is stream velocity fastest?

Near the surface.

What is the equation for discharge?

Q = w × d × v (width × depth × velocity)

What is the stream power equation?

Ω = ρ × g × Q × S (density × gravity × discharge × slope)

What are the types of erosion?

* Corrosion (chemical) * Corrasion (abrasion) * Cavitation (bubble collapse)

What is entrainment in sediment transport?

Occurs when bed shear stress exceeds particle friction.

What are the modes of sediment transport?

* Solution (dissolved) * Suspension (fine particles) * Saltation (bouncing) * Traction (rolling/sliding)

What differentiates uplands from lowlands in land systems?

* Uplands: erosion-dominated, high stream power, deep channels * Lowlands: transport/deposition-dominated, low stream power, floodplains

What characterizes bedrock channels?

Erosion via abrasion, plucking, cavitation.

What features are associated with bedrock channels?

* Waterfalls * Plunge pools * Potholes * Rapids * V-shaped valleys

What are alluvial channels composed of?

Unconsolidated sediments, influenced by stream power and sediment supply.

What are the types of alluvial channels?

* Alluvial fans * Meandering (sinuosity >1.5) * Braided (multiple channels)

What features are found in floodplains?

* Levees * Oxbow lakes * Crevasse splays * Abandoned channels

What do terraces record?

Environmental changes (climate, hydrology). Types: paired, unpaired, straths.

What shapes coastlines?

Marine processes.

What are the types of coasts?

* Hard (rocky, slow change) * Soft (sediment, rapid change)

What are the properties of waves?

* Height * Length * Steepness * Period

What processes do waves undergo?

* Shoaling * Refraction * Reflection * Breaking

What are the mass transfers in the surf zone?

* Swash * Backwash * Littoral currents (alongshore sediment transport) * Rip currents

What affects tidal speeds?

Tidal range affects wave breaking zone.

What conditions create storm surges?

High tide + low pressure + wind.

What are the tidal regimes?

* Microtidal (<2 m) * Mesotidal (2–6 m) * Macrotidal (>6 m)

What are deltas formed by?

Sediment deposition at river mouths (fluvial-, wave-, tide-dominated).

What is an estuary?

Where freshwater meets the sea; lagoons are enclosed saline waters.

What are the processes occurring in coastal environments?

* Mixing * Flushing * Flocculation

What are the compositions of beaches?

* Sand * Gravel * Mixed

What are the features of hard coasts?

* Wave-cut features: notches, platforms, arches, stacks, ribbon beaches

What are the reasons for modifying rivers?

* Flood Prevention * Erosion Control * Stream Restoration

What is channelization?

River engineering for flood control, drainage improvement, erosion reduction, navigation support.

What are the types of channelization?

* Re-sectioning (widen/deepen channel) * Realignment (straighten river) * Diversions (change river path) * Embankments (contain floods)

What methods protect river banks?

* Groynes * Fences * Revetments * Gabions * Riprap * Fascines

What are lined channels made of?

Concrete (low roughness → ↑ velocity)

What are the types of glaciers?

* Valley Glaciers * Ice Sheets * Ice Shelves

What are the thermal types of glaciers?

* Cold (Polar) * Warm (Temperate) * Polythermal

What is glacier mass balance?

Inputs: Snow, Rain, Avalanches, Regelation ice. Outputs: Melt, Sublimation, Calving, Deflation.

What are the zones of glacier mass balance?

* Accumulation (Gain) * Ablation (Loss) * ELA (Equilibrium Line Altitude)

What happens when ELA decreases?

Positive balance: glacier grows.

What happens when ELA increases?

Negative balance: glacier shrinks.

What is internal deformation in glaciers?

Dominates in cold glaciers; described by Glen’s Flow Law.

What is sliding in glaciers?

Water at base lubricates faster movement; common in temperate/polythermal glaciers.

What occurs during subglacial sediment deformation?

Soft, saturated beds deform, allowing the glacier to slide.

What are flow features in glaciers?

* Crevasses * Streamlines

What drives Quaternary Environmental Change?

Repeated glaciations & interglacials driven by Milankovitch cycles.

What evidence supports Quaternary Environmental Change?

Ice cores, sediments confirm patterns.

What are examples of environmental hazards?

* Floods * Earthquakes * Landslides

How does climate change affect environmental hazards?

Increases hazard frequency/severity.

What are the two systems of hazard management?

* Natural Events * Human Use

What strategies are used for hazard management?

* Modify Event (Engineering) * Modify Human Activity (Education, land use, insurance)

What is the main takeaway regarding environmental change?

Environmental change is long-term + ongoing.

Geomorphology Flashcards

(76 cards)