Week 12, Floods and Impacts from Space Flashcards

1
Q

Rainfall floods

A

Occur due to precipitation that exceeds ability of river

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2
Q

Slow rainfall floods

A

Sustained heavy rains

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3
Q

Flashfloods

A

Thunderstorms, intense and fast

  • rain event is larger than the bearing capacity of the soil
  • fatalities often related to driving through flood intersections
  • most common in desert areas because dry soils won’t absorb water
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4
Q

Why was the Alberta 2013 flood considered to be the flood of floods?

A
  • largest evacuation in Canada in the past 60 years
  • triggered by significant rain
  • large mountain snowpack, high ground water table
  • wet spring saturated soils
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5
Q

What kind of flood is the most common in Canada?

A

Snowmelt flood

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6
Q

Rain on snow flood

A

Combine rainfall and snow melt events. Rain causes even more extreme melting.

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7
Q

Icejam floods

A

Occur mostly on rivers that flow from South to North

Accumulation of ice fragments that act as a temporary obstruction, restricting water flow. Can occur during freeze up or break up.

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8
Q

Natural dams can be formed by

A

glaciers, mass movements, or lava and pyroclastic flows.

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9
Q

Jökulhlaups

A

Glacial outburst floods

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10
Q

Flood frequency curves give us

A

historical data on floods.

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11
Q

Extraterrestrial impacts can be due to

A

Asteroids and Comets

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12
Q

Fragments of asteroids and comets can be referred to as

A
  • meteoroids: before impacting earth
  • meteors: while passing through atmosphere
  • meteorites: after impacting earth
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13
Q

Asteroids

A
  • Stoney/metallic bodies that orbit the sun
  • Medium size
  • Planetoids or minor planets
  • Mostly in asteroid belt between Mars and Jupiter
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14
Q

3 smaller groups of asteroids with orbital paths that intersect orbits of Earth/Mars

A

Apollos
Aten
Amars

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15
Q

Comets

A
  • Small bodies, highly elliptical solar orbits

- Mostly water, ice and frozen gases. With some rock and dust.

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16
Q

Meteorites

A
  • Stoney fragments of a comet or asteroid

- Iron-rich

17
Q

The atmosphere can protect the Earth from meteorites depending on their

A

size.

18
Q

Simple craters

A

Rim, concave bottom, cause by small meteoroids.

19
Q

Complex craters

A

Resembles water drop, impact then we experience rebound and uplift.

High temperature and pressure vaporize object and rock.

20
Q

What erased evidence of crater/impact?

A

Weather, erosion, and tectonic processes.

21
Q

What happened in the KT impact?

A

Mass extinction- 85% of all species were erased from the earth

22
Q

How can we explain KT extinction?

A

Clay contain quartz grains with “shocked” structure

More Iridium in clay than usual

Mineral spherules are present indicating a melt

Radioactive element ratios similar to meteorites