Midterm (1-6) Flashcards Preview

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Flashcards in Midterm (1-6) Deck (107)
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1
Q

Hazard

A
  • probability that a specific damaging event will take place within a particular period of time
  • events are not a hazard but become so because of human use of land
2
Q

Risk

A
  • probability of a hazardous event and the expected damage if the event does occur
3
Q

Catastrophe

A
  • massive disaster that requires significant expenditure of money and a long time (years) for recovery to take place - Hurricane Katrina
4
Q

Disaster

A
  • hazardous event that occurs over a limited time span in a defined area
  • criteria: (1) 10+ people killed (2) 100+ people affected (3) state of emergency declared (4) emergency assistance is required
  • if 1 occurs it is a natural disaster
5
Q

Main Impacts

A
  • loss of life

- damage to infrastructure (transportation, health services, residences)

6
Q

Vulnerability

A
  • attributes, activities and aspects of a person/community that increases their susceptibility to given dangers
7
Q

6 Forms of Vulnerability

A
  1. exposure to dangerous agents and environments
  2. weakness - predisposition of persons, buildings, communities or activities to greater harm
  3. lack of protection
  4. lack of resources to affect risks or respond to danger
  5. no capability to avoid/withstand or offset and recover from disaster
  6. inability to influence safety conditions or acquire protection and relief
8
Q

Resilience

A
  • measurement of vulnerability and how quickly a community can recover from disaster
9
Q

Direct Effect

A
  • people killed, injured, dislocated or otherwise damaged by a particular event
  • felt by fewer people
10
Q

Indirect Effect

A
  • responses to the disaster (emotional distress, donation of money or goods, paying of taxes levied to finance recovery)
  • felt by many people
11
Q

Prediction

A
  • specifies date, time and size of event
12
Q

Forecast

A
  • has ranges of certainty (i.e. weather)
13
Q

Probability of Occurrence

A

determining the probability of an event in a particular location within a time span

14
Q

Precursor Events

A
  • hazardous events are preceded by precursor events
    o i.e. surface of ground may creep prior to landslide
    o Identification of precursor event help predict when and where a major event is likely to happen
15
Q

Warning

A
  • after a hazardous event has been predicted or forecast has been made, public must be warned
16
Q

Magnitude vs. Frequence

A
  • Magnitude: function of the amount of energy released

- Frequency: the interval between occurrences

17
Q

Structural Adjustment

A
  • design of better building material and structural design that reduces the impact on the structure
  • more for floods and landslides
18
Q

Non-Structural Adjustment

A
  • legislation, planning, insurance, education, warnings
19
Q

Faults

A
  • fracture where rocks have been displaced
20
Q

Descriptors

A
- Indicate the location of the fault line and point at which the quake originated:
o	Point of origin
o	Focus
o	Hypocenter
o	Epicenter
21
Q

Seismic Waves

A
  • Main determinant of earthquake hazard is the land waves generated from force of rupture
  • Travel through land and at surface causing shaking of the ground
22
Q

Reservoirs

A
  • Dams enable communities to survive in regions where water resources are limited
  • Essential in drought prone regions to provide water for agricultural irrigation and human consumptions
23
Q

Deep Waste Disposal

A
  • The disposal of unwanted liquids into bedrock has been linked to earthquake activity at a number of sites
  • Liquid increases fluid pressure and causes slippage and fractures in bed rock
24
Q

Pumping of Oil and Gas

A
  • Removal of liquid and gases from bedrock can trigger quake activity (Alberta, BC)
25
Q

Hydraulic Fracturing

A
  • “Fracking” is cause of earthquake in regions of oil and gas productions
26
Q

Divergent Boundaries

A
  • A linear feature that exists between two tectonic plates that are moving away from each other.
27
Q

Convergent Boundaries/Subduction Zone

A
  • Also known as a destructive plate boundary (because of subduction), is an actively deforming region where two tectonic plates move together and collide
28
Q

Transform Boundaries

A
  • A fault whose relative motion is horizontal
29
Q

Type of Faults

A

Strike-slip: horizontal displacement of fault plane

Thrust: hanging wall moves up and over footwall

Normal: footwall moves up and hanging wall moves down (opposite movement is called reverse fault)

30
Q

Richter Scale

A
  • based on a scale of 10
  • The readings help determine the level of magnitude of an earthquake
  • Derived from the logarithm of the amplitude of waves, recorded by a seismograph
31
Q

Mercalli Scale

A
  • focuses more on impact to society (# deaths, buildings collapsed)
  • 3 WEAK: Felt by nearly everyone; some damage to wall plaster; unstable objects are overturned
  • 4 WEAK: Felt on upper floors of buildings; stationary cars may rock slightly; vibration feels like the passing of a truck
  • 8 SEVERE: Few masonry structures remain standing; bridges are destroyed; landslides are common
  • 2 WEAK: Felt by very few people
32
Q

Primary Hazards

A
  • Primary damage that occurs is related to shaking of the ground and subsequent failure of structures (injuries and death)
33
Q

Secondary Hazards

A
  • liquefaction
  • landslides
  • land level changes
  • tsunami
34
Q

Tertiary Hazards

A
  • When the initial hazard lead to the initiation of other hazards not always directly associated with the initial hazard
  • fire, flood, exposure, disease, stress
35
Q

Conditions that Create Vulnerability

A
  • construction material (quality, availability and cost)
  • building design (doors, windows, roof lines, room layout)
  • upkeep and renovations (improve structural strength)
  • site and situations (stability of foundations and closeness to slopes and other structures)
36
Q

Short Term Predictions

A

Make predictions by observing:

  • Foreshocks: tracking the rate of small shocks it is possible an increase in activity will provide warning of a larger earthquake
  • Patterns and frequency of earthquakes and foreshocks
  • Deformation of the ground surface including uplift and subsidence
  • Seismic gaps along faults where there are sites of inactivity
  • Geophysical and geochemical changes in groundwater levels, temperatures, soil and water chemistry
37
Q

Tephra

A

the material explosively released during volcanic activity

38
Q

Types of Volcanos

A
  1. Stratovolcano or Composite Volcano
  2. Shield Volcano
  3. Volcanic Domes
  4. Cinder Cones
39
Q

Humans & Volcanos

A
  • One of the few hazards we study that have little evidence of human activity affecting them.
  • The level of human activity required to create a volcano is not often reached intentionally or unintentionally.
40
Q

Benefits of Volcanos to ecosystem

A
  • Volcanic soil (create rich soils attractive to farming)
  • Geothermal power (alternative energy source, mining heat from earth)
  • recreation (tourism attractions)
41
Q

Volcanic Explosivity Index (VEI)

A
  • measure of the volume of material erupted and the height of the ash plume.
  • starts at 0 and no upper limit exists
42
Q

Pillow Lava Flow

A
  • occurs when hot lava flows into water and cools rapidly, creating long tubes and bulbous pillow-shaped mounds of rock.
43
Q

Pahoehoe Lava Flow

A

characterized by a smooth, billowy, or ropy surface, ropy surface develops when a thin skin of cooler lava at the surface of the flow is pushed into folds by the faster moving, fluid lava just below the surface, flows tend to be relatively thin, from a few inches to a few feet thick

44
Q

AA Lava Flow

A

Characterized by a rough, jagged surface, flows advance much like a bulldozer

45
Q

Ash Fall

A
  • Fine-grained fragmented debris, ash and abrasive volcanic glass
  • Large eruptions cover property and can cause breathing problems and plane crashes.
46
Q

Pyroclastic Flow

A
  • Explosive volcanoes produce an incinerating mixture of gas and debris measuring between 700°-1000°C called pyroclastic flow.
  • This fast-moving (150 km/h) flow burns everything in its path as it moves down the flank of the volcano.
  • The flow can erupt vertically or from the side, which is a more deadly, concentrated flow.
47
Q

Lahar - Volcanic Mudflow

A
  • mixture of water and debris from the volcano
  • The hazard of lahar is related to moisture conditions - greater moisture content will have a higher velocity and lower viscosity
48
Q

Poisonous Gases

A
  • main component of poisonous gases is water vapour (CO2, CO)
  • Other gases, such as hydrogen sulfide (H2S), sulphuric acid (H2SO4) and hydrochloric acid (HCl) are created which cause acid rain and burning in humans and vegetation
49
Q

Methods to Identify Possible Volcanic Activity

A
  1. Ground Deformation - Land Surface Monitoring
  2. Seismicity
  3. Remote Sensing
  4. Volcanic Gases
  5. Geologic History
  6. Hydrologic Hazards
50
Q

Alert: Normal/Green

A

Non-erupting volcano is exhibiting typical background activity (including steaming, seismic events, thermal feature, or degassing)

51
Q

Alert: Advisory/Yellow

A

Volcano is exhibiting signs of elevated unrest above known background activity.

52
Q

Alert: Watch/Orange

A

Volcano is exhibiting escalating unrest with increased potential of eruption, timeframe uncertain OR an eruption is underway that poses limited hazards including no or minor volcanic-ash emissions.

53
Q

Alert: Warning/Orange

A

Major volcanic eruption is imminent, underway, or suspected but it poses limited hazards to aviation because of no or minor volcanic-ash emissions

54
Q

Alert: Watch/Red

A

Volcanic eruption is underway that poses limited hazards to ground-based communities but includes significant emission of ash into the atmosphere that could affect aviation

55
Q

Alert: Warning/Red

A

Major volcanic eruption is imminent, underway, or suspected with hazardous activity both on the ground and in the air.

56
Q

Tsunamis

A

A long high sea wave caused by an earthquake, submarine landslide, or other disturbance

57
Q

Mega-tsunami

A

Produced by asteroid impact; wave that is about 100 times higher than the largest tsunami produced by an earthquake

58
Q

2 ways that earthquakes can cause a tsunami

A
  1. Movement of the seafloor

2. Triggering a landslide

59
Q

Distant/Tele-tsunami

A

Travels out across the deep ocean at high speed

Travels at least 1000 km before reaching land

60
Q

Local tsunami

A

Heads towards land , can arrive quickly following an earthquake

61
Q

Characteristics of regions at risk of tsunamis

A

Geographic location of a cost in relation to potential tsunami sources; earthquakes, landslides, volcanos

62
Q

Rogue wave

A

Waves that are greater than twice the size of surrounding wave and are very unpredictable

63
Q

Storm surge

A

A rising of the sea as a result of atmospheric pressure changes and wind associated with a storm

64
Q

3 main processes that lead to displacement of water

A
  1. Earthquake must register at least a 7 on the Richter scale
  2. Seabed must be lifted or lowered by the earthquake
  3. Epicentre of earthquake must be near to the earth’s surface
65
Q

4 stages of tsunamis

A

Stage One: Earthquake rupture in the seafloor pushes water upwards

Stage Two: Tsunami moves rapidly in deep ocean, reaching speeds of 950km/hr

Stage Three: As the tsunami nears land it slows to about 45km/hr but is squeezed upwards increasing in height

Stage Four: Tsunami heads inland, destroying all in its path

66
Q

Least common trigger of tsunamis

A

volcanic

67
Q

Natural function of tsunamis

A

Rejuvenate the vegetation cover, creating new habitats and possibly over time increasing biodiversity

68
Q

Which ocean is most likely to experience a tsunami

A

85% of tsunamis occur in the Pacific ocean

69
Q

What countries are most at risk of a tsunami?

A

Japan, Kamchatka, Hawaii, islands in the southern and west Pacific, Chile, Peru, Mexico, and the northeast Pacific coast from Alaska to northern California

70
Q

Minimizing the tsunami hazard

A

Detection and warning, structural control (walls and dykes), construction of runup maps, land use, probability analysis, education, tsunami-ready status

71
Q

Tsunami runup map

A

Shows the level to which the water travelled inland

72
Q

Tsunami watch

A

Notification that an earthquake that can cause a tsunami has occured

73
Q

Tsunami warning

A

Tsunami has been detected and is coming

74
Q

Inundation maps

A

Predict and display the extent that waves will run up the shoreline and inundate the adjacent land.

75
Q

3 recent canadian tsunamis

A
  1. Halifax, Nova Scotia (1917)
  2. Port Alberni, British Columbia (1964)
  3. Kitimat Inlet, British Columbia (1975)
76
Q

5 basic types of landslides

A
  1. Falling: free fall of earth material
  2. Sliding: downslope movement of coherent block of earth along a plane
  3. Flow: downslope movement of unconsolidated material
  4. Slumping: sliding of rock or soil along a curved plane
  5. Creep: very slow flowage
77
Q

Forces that impact landslides

A

Driving forces

Resisting forces

78
Q

Calculating factor of Safety

A

resisting forces/driving forces

79
Q

Variables that impact driving and resisting forces

A
Material type
Slope and topography
Climate
Vegetation
Water
Time
80
Q

Debris flow

A

Thick mixtures of mud, debris, and water; can move fast or slow, depending on conditions

81
Q

Structural controls of landslides

A
  1. Slope drainage
  2. Slope reduction
  3. Engineering to resist mass movement
  4. Engineering to mitigate damage
82
Q

Human processes in the initiation of landslides

A

Timer harvesting
Urbanization
Mining

83
Q

Conditions to be considered in the prediction of landslides

A
  1. Slopes and seismic activity
  2. Geology and structure
  3. Surface water buildup
  4. Topographic and vegetation features
  5. Accelerated creep
84
Q

Drainage basin

A

Region drained by a single stream or river

85
Q

Discharge

A

Volume of water moving through a cross section of a river per unit of time

86
Q

3 channel patterns of streams and rivers

A
  1. braided: large number of intersecting active channels
  2. anastomosing; 2+ channels and intervening stable islands or bars where sediment is temporarily stored
  3. meandering: single channel shaped like a snake
87
Q

Flash flood

A

Associated with intense rainfall events such as during convective thunderstorms

E.g. Saguenay River in Quebec (1996)

88
Q

Regional Floods

A

Cover large areas in extensive river valleys with flat topography

E.g. Red River in Manitoba

89
Q

Impacts of floods

A

Primary Impacts:

  • Loss of life, primarily from drowning
  • Injury
  • Damage to structures
  • Soil and vegetation erosion and deposition

Secondary Impacts

  • Pollution
  • Hunger
  • Disease
  • Displacement of people
  • Losses of services and income
90
Q

Structural and non-structural adjustments for floods

A

Structural Adjustments

  • Floodproofing
  • Channelization

Non-Structural Adjustments

  • Floodplain Regulation
  • Relocation
  • Channel Restoration
91
Q

Hydrograph

A

Graph showing changes in stream discharge, water depth, or stage over time

92
Q

Flood stage

A

When the elevation of the water surface has reached a level likely to cause damage to personal property

93
Q

Recurrence interval of a flood

A

Average time between flood events that are of equal or greater magnitude

94
Q

Downstream flood

A

Covers wide areas and are caused by regional storms or spring runoff

95
Q

Natural service functions of floods

A

Fertile lands
Aquatic ecosystems
Sediment supply

96
Q

Channelization

A

Straightening, deepening, widening existing stream channels

97
Q

Watershed or catchment

A

An area that contributes surface water to a stream

98
Q

Gradient

A

The average slope of a stream channel; that is, the ratio of the vertical drop of the stream over the horizontal distance of the drop

99
Q

Headwaters

A

The tributaries of a stream or river near its source

100
Q

Base level

A

The theoretical lowest elevation to which a river can erode at a particular time

101
Q

Stream or total load

A

The sum of the dissolved, suspended, and bedload that a stream or river carries

102
Q

Epicenter

A
  • where earthquake starts

- place on the surface of Earth above where the ruptured rocks broke to produce the Earthquake

103
Q

Focus or Hypocenter

A
  • point of initial breaking

- directly below epicenter

104
Q

Earthquake cycle

A
  1. long period of inactivity along a segment of a geologic fault.
  2. accumulated elastic strain produces small earthquakes. 3. consists of foreshocks, may occur only hours or days prior to the next large earthquake (stage may not occur)
  3. The mainshock, the major earthquake, and its aftershocks
105
Q

Strain

A

deformation resulting from stress

106
Q

elastic strain

A

deformation that isn’t permanent provided that stress is eventually released

107
Q

elastic rebound

A

occurs after an earthquake