Natural Disasters Midterm
Terms in this set (115)
Why are Natural Disasters considered 'unnatural disasters'?
• Natural Disasters are a blend of natural and unnatural (human-caused) elements
• Misuse of human environment, E.x.: deforestation (flooding & mudslides)
• Human settlements: location, building quality and community design
What are natural disasters?
• Natural disasters are all the potential threats facing human society by events that originate in, and are transmitted through, the environment
What is a hazard?
• A hazard is an event or phenomenon with potential to create damage/loss (a source of danger)
What is risk?
• Risk is exposure of something of human value to a hazard (people, goods, environment)
What is a disaster?
• A disaster is the realization of a hazard
• There is no agreement on what a disastrous event is (E.x., how many have to be dead?)
• Factors creating disaster:
• Time: rapid vs. slow / random vs. predictable / rare vs. common
• Spatial Connections: localized vs. extensive / single vs. multiple / expected vs. unexpected
Explain temporal aspects of disasters.
• Magnitude vs. Frequency: low magnitude events are more frequent (E.x., F1 tornado vs. F5 tornado)
• Magnitude vs. Recurrence Interval: long recurrence intervals equal high magnitude events (10 year flood vs. 1000 year flood)
Explain spatial aspects of disaster.
• Total Impact = disaster relief supplies & personnel, local relief, no physical damage & many refugees, some damage & injuries, deaths & structural collapse
According to the Centre for Research on the Epidemiology of Disasters, what is a 'disaster' and 'significant disaster?
• Disaster is >10 dead or >100 affected
• Significant Disasters are >100 dead or economic damages of >1% of GDP or >1% of affected population
What are the different types of natural disasters?
• Hydrological (floods), meteorological (cyclonic storms, lightning), geophysical (landslides, tsunami, volcano, earthquake), and biological (wildfires, pests)
• Context Hazards: air pollution, sea level rise, climate change, desertification, etc.
• Technological Hazards: transport accident, industrial accidents, nuclear accidents
• Complex Hazards: primary hazards can lead to second and even tertiary hazards: Cyclone > extreme weather > flooding > disease
What is the difference between single events vs. combination events?
• Given the example of atmospheric hazards, a single event is something like rain or hail or ice ... a combination event is something like hurricanes, ice storms, thunderstorms, etc.
What are some biological hazards that we face?
• human epidemics (Aids, malaria)
• plant epidemics
• animal epidemics (mad cow)
• invasions or introduced species (cane toad)
Hazard Topology: what value is there in classifying natural disaster?
• Allows an organization of complexity and diversity
• Allows for a standardization
• Highlights connections/complex hazards
• Gives us a checklist for: mapping and prediction risk, assessing community vulnerability and mitigation and disaster preparedness
What is the importance of natural disasters? Why care?
• Annual damage in worldwide foreign aid: $120 billion yearly
• 100,000 deaths and at least 40 million affected yearly
• There is no hazard-free location on Earth
Does deadliest disasters always equal costliest?
• No, most of the deadliest disaster occur in China (>90% of deaths in LDCs)
• Most of the costliest disaster occur in North America due to the amount of spending on engineering and safety (>75% of economic damage in DCs)
What are some damage/death trends in natural disasters (excluding BioHazards)?
• Damages, people affected, and disasters were increasing from 1963-2000
• Deaths began decreasing from 1900-2010
• Usually very young (<10) and older (>55) people are being killed
Natural Hazards Research: who is accredited with the beginning of systematic research on hazards?
• (1940s) Gilbert F. White
• studied impact of expenditures
• single hazard research (floods)
• came up with "levee effect": levees used to prevent overflow of water onto the channels banks
• the result: flood damages increased!
• 1936: Flood Control Act in US (engineering measures, billions spent)
• Proliferation of hazard research after White
Measuring Hazards: Earthquakes? Tsunamis? Volcanoes? Landslides? Snow Avalanche? Hurricanes? Tornadoes? Frost? Flood? Drought?
• Measuring phenomenon:
• Earthquakes measured on Richter scale (open-ended)
• Tsunamis measure in maximum wave run-up
• Volcanoes measured in volcanic explosivity index (VEI)
• Hurricanes measured in Saffir-Simpson scale (windspeed: 1-5)
• Measuring damage:
• Landslides measure in damage intensity scale (1-7)
• Avalanches measure in impact pressure (tonnes/sq.m)
• Measure phenomenon & damage:
• Tornadoes measure in Fujita (F1-F5) & Pearson scales (0-5)
• Frost measure in agricultural frost risk scale (0-4)
• Floods measure in recurrence intervals (open-ended)
• Drought measured in Palmer drought severity index (PDSI)
Why is it difficult to relate all disaster-related deaths directly to the initial hazard?
• Because so many deaths come from secondary and tertiary disasters
• E.x.: Flood Event > drowning > water-borne disease > untreated injury > famine
What is vulnerability?
• The characteristics of a person or group in terms of their capacity to anticipate, cope with, resist and recover from the impact of a natural hazard
• Vulnerability is the risk of hazard + relative ability to cope with disaster and depends on:
• setting, expectation, magnitude, socioeconomic levels, preparedness, community, emergency services, gender, age
What is the "Pressure and Release Model (PAR)" of vulnerability?
• Root Causes (E.x., poverty) > Dynamic Pressure (E.x., environmental change) > Unsafe Conditions (E.x., informal housing on floodplain) > DISASTER < Natural Hazards
• review diagram
What is the 'vulnerability of place model'?
• More of a classic geographers view of vulnerability
• "Cutter developed an integrative approach (hazard of place), which tries to consider both multiple geo- and biophysical hazards on the one hand as well as social vulnerabilities on the other hand" (wiki).
Explain the difference between: direct, indirect, tangible, and intangible losses from disasters.
• Direct: immediate impacts of disaster
• deaths, injuries, shock, building collapse, personal belongings destroyed, crop/anima/land loss
• Indirect: lagged impacts of disasters
• stress, mental illness, disease, loss of business, tourism
• Tangible: a possibility to assign a money value
• Intangible: difficult to assign a money value
• desire to live in a location that caused death
Explain the difference between direct and indirect gains from disasters.
• Direct Gains: aid (money, housing, food), employment (rebuilding), environmental gain (soil fertility, land)
• Indirect Gains: international profile, tourism, community cohesion, improved buildings
Why should we study hazards and disasters?
• To reduce damage and human suffering
• It is an applied knowledge
• Because it is fascination (human psychology)
• Growth industry
• Growing human causes:
• urbanization, wetland drainage, deforestation, global warming, settlements
Who are the actors in human response to hazard?
• NGOs & For-Profit Companies
• Communities and Societies
• Media and Celebrities
What is a response to disaster?
• All the ways in which a society may act to reduce the negative effects, or increase positive benefits from hazards
Explain the difference between adaptation and adjustment.
• long-term, may be fairly 'unconscious'
• cultural adaptations: land ownership, membership to organizations, etc.
• Adjustment: (bear, share, reduce)
• do nothing (bear the loss)
• do something to share the loss
• do something to reduce the loss (modify the hazard, modify human vulnerability and reduce human exposure to hazard)
Explain the difference between structural adjustment and non-structural adjustment.
• safe building measure (safer structures, protection of facilities, strengthening existing structures, etc.)
• disaster management (risk reduction)
• public awareness (education & training)
• laws/controls (bylaws and codes of practice and land use)
• insurance (individual and community insurance)
One of the adjustments to a disaster is to 'do nothing'. Why?
• The claim in LDCs is that powerful social forces influence citizens and make hazards impossible to share or reduce (such as poverty or population or lack of employment or education)
• These LDC citizens repeatedly suffer losses because of their lack of response
Loss-Sharing organizations: where does the aid/foreign aid come from?
• money from countries (international organizations)
• World Bank, etc.
• government-to-government aid
• Federal & Municipal Agencies:
• emergency services
• specialized agencies within the region served
• NGOs (charities):
• funded by direct appeal, grants from multilateral/bilateral aid
How can we modify the hazards?
1. Total Prevention
• dams, spillways, levees, health programs, restrictions, etc.
2. Magnitude Reduction
• afforestation, dams, stormwater ponds, avalanche control, lahar diversion channels, snow sheds, seawalls, breakwaters, beach stabilisation, etc.
How can we modify human vulnerability?
• Adjusting people & property to reduce/minimize loss
• Predictions, forecast, and warnings
• Risk assessment/mapping
• Regional planning, land use planning and zoning
• Protection Structures
• Building codes and hazard resistant design
• Financial and tax incentives
• Public Education
• Emergency preparedness and disaster management
Volcanoes: How many active volcanoes are there in the world?
Volcanoes: Where are they mostly located?
• 90% at edges of tectonic plates (rift)
• 10% due to hot spots
How many volcanoes erupted in the last 10ky?
How do we classify volcanoes?
• active (erupted within the last 25,000 years), dormant, extinct
• there is no certainty to classification
What percentage of the world's population lives near active volcanoes?
Volcanic Hazards: What are some components of overall hazard?
• pyroclastic flows (70% of all killed), blasts, primary lahar (lake eruption), air fall tephra (dust, ash), laval, VOG (volcanic gas), secondary lahar, ground deformation, earthquakes, landslides, tsunamis, etc.
Mt. St. Helens 1980: How many died? How much damage? Components?
• 62 killed
• $1billion in damage
• landslides, blasts, pyroclastic flow, lava and ash, lahar and mudflow
Damages: How many volcanic deaths from 1900-2000?
• 1000 killed per year (2 events = 51,000 deaths)
What are some of the worst volcanic disasters?
• 1881 Krakatoa (indonesia): 33,000 killed
• 1902 Mt. Pelee: 28,000 killed
• 1985 Ruiz (Colombia): 23,000 killed
What percentage of eruptions actually cause death?
What are some of the most damaging eruptions?
• St. Helens 1980 ($1 billion)
• Iceland 2010 ($1.7 billion)
How has the volcanic disaster changed?
• Previously, most deaths due to secondary hazards such as famine
• Today, most deaths are due to direct hazards such as pyroclastic flows and lahars
What are some human dimensions of volcanoes?
• human settlements on active volcanoes, pressure buildup near settlements, recreation
How is form an indicator of danger for volcanoes?
• beautiful volcanoes are dangerous volcanoes: steep, symmetrical, concave
How often do VEI 5 eruptions occur? VEI 7?
• VEI 5 every 10 years
• VEI 7 every 100 years
What types of monitoring do we use for volcanoes?
• seismic, ground deformation (tilt-meters), VOG chemistry, water chemistry, thermal, magnetic, gravitational, electrical
Volcanoes: How many out of the people who are told to evacuate stay behind? Why?
• 29% choose to wait or only evacuate some of the family
• didn't want to leave property, thought the eruption wouldn't be strong, harvest time, no vehicle, didn't know where to go, god would protect them, thought eruption was over, etc.
What is mass movement? What kinds are there?
• The displacement of surface materials down-slope under the force of gravity
• Slow (erosion, creep) or Rapid (landslide, rockfall, mudslide, avalanche)
What is the key factor for mass movement?
• slope steepness
Mass Movement: Where do most deaths occur?
• 90% of deaths are along the Pacific Rim
• Tropical areas at particular risk because of heavy rainfall events, and debris flow
• Human-caused mass movements dramatically increasing worldwide
What was the largest modern debris flow disaster?
• Caracas, Venezuela 1999 (>30,000 killed)
Mass Movement: What was the deadliest event recorded?
• Shaanxi, China 1556 (830,000 killed)
What are some important factors of mass movement?
• Rain, soil type, ground cover, steepness, faulting
November 2003, Indonesia had a major debris flow. Why?
• rainfall, deforestation, illegal logging, road-building, settlement location
Mass Movement: What are the hazard components (things that could cause death or injury)?
• impact pressure and debris movement
• cover: land degradation (suffocation)
• drowning (debris flows, mudflows)
• secondary hazard trigger (tsunami, flash flood)
Mass Movement: How many deaths in the '70s? '90s?
• 1970: >600 deaths per year
• 1990: >4000 deaths per year
What is a long-runout debris flow?
• a special category of landslide (complex slide)
• most slides travel horizontally <2x vertical fall
• long-runout debris flows 2-25x length of vertical fall
• causes: air cushion, water saturation theory, vibration fluidization
What is a avalanche?
• a special category of mass movement (snow as the mass)
• triggers: recreational skiing, noise, temperature & rain
• smaller range of slopes (20-60 degrees)
• most avalanches occur at 30-45 degree slopes
• origins: fracture points with snow (slope changes)
• two types: loose snow and slab (most destructive)
• speeds range from creep to >350 km/h
Where are most avalanches?
• high mountain cold environments
Avalanches: How many deaths world wide?
• <250 deaths per year
Why is erosion not usually seen as a natural hazard?
• slow, natural/normal, invisible
Why is erosion a concern?
• can trigger rapid-onset events
• can be linked to other natural disasters: flood, coastal storm surge, volcanic eruption, dust storm, drought
What is erosion?
• movement of rock, sediment or soil by erosive agents + gravity
What are the causes of erosion?
1. natural physical processes (wind & water)
2. human causes
• ground disturbances, changes in water flow, vegetation disturbance (deforestation, grazing, human settlement), climate change
3. thermal erosion
• direct: permafrost melting
• indirect: ice cap melt, sea-level rise, erosion, enhance storm activity
What is an earthquake?
• a generic term used for any Earth vibration no matter what cause
• usually do to plate tectonics
• dip & slip components to fault slippage
Worldwide distribution of earthquakes: how many deaths from 1900-2000?
• 1.5-2 million deaths
• Earthquakes kill greatest numbers in a band from Indonesia to East European
• The time of day is critical in detraining casualties
How many fatal earthquakes from 1900-2000?
• >1000 fatal earthquakes
What are some earthquake impacts?
• deaths, property destruction, physical injury, geological spinoffs, psychological impacts, economic disruption, ecological/habitat change
What are some earthquake hazard components (first, second, third components)?
• First component: Earthquake
• Second: landslide, ground movement, ground liquefaction, tsunami
• Third: flood, structural failure, flood
• Forth: drowned, burned, electrocuted, crushed
What are the 4 main types of shockwaves from earthquake seismology?
1. Primary (P) Wave
• compressional or push-pull wave that can be heard
• fastest type, first to be felt
2. Secondary (S) Wave
• transverse or wiggling wave
• damaging, due to shaking effects
3. Love Wave
• side to side motion
• highly damaging
4. Rayleigh Wave
• backward rotating motion
What are the two types of scales used to measure earthquakes?
• effects on people & buildings
• quantitative measure of energy released
Earthquakes: How is magnitude measured?
• Richter Scale: seismograph amplitude, good for nearby, moderate quakes
• Moment Magnitude Scale: energy released, requires a lot of technology, best for high magnitude events
What is an aftershock?
• quakes which follow a mainshock
What is a swarm?
• clusters of quakes closely spaced in time and space (no mainshock)
What is a earthquake storm (theory)?
• earthquake creates stress further along fault
• months/years later additional earthquakes
• future mega-event could be in Istanbul due to two nearby earthquakes (60-70% chance of being struck by a major earthquake within the next 30 years)
What does earthquake vulnerability depend on?
• expectation, seismicity of area, building design, construction standards, pre-disaster planning, post-disaster services, geologic features, timing
What is liquefaction?
• the process whereby soil saturation with water is shaken by an earthquake, causing the soil to lose its ability to support loads and begin to behave like a liquid
Tsunami: What does the word mean?
• Tsu: harbour and Nami: wave
What are they caused by?
• caused by rapid movement of sea water
• earthquakes, volcanic explosion, undersea landslides, meteorite, mass movement into ocean
• usually multiple tsunamis from one event
How are they measured?
• wave run-up in meters
What is the hollywood stereotype of tsunamis?
• a perfect single wave
Tsunami: What does it really look like?
• pancake effect of waves pushing into each other
Nature of Hazard: How fast do the waves travel across a deep ocean? Shallow water?
• 600-850 km/h across ocean
• <100 km/h in shallow water
Tsunami: Which are the most dangerous?
• shallow topography, harbours & bays, lagoons
How often do we see damaging tsunamis each year?
• 2 damaging tsunamis per year
Tsunami: How many deaths from 1904-2004?
• 50,000 deaths
Tsunami: How many deaths in 2004?
Tsunami: Where do most tsunamis occur?
• >25% of all tsunamis from Japan-Taiwan island arc
Tsunami: What are the hazard components (how could you die)?
• drowning and battering/scouring of waves/debris movement
Tsunami: Who is most at risk?
• children, elderly, poor
Tsunami Monitoring: how are tsunamis predicted?
• seismograph (earthquakes), tide gauges (wave movement), bottom pressure recorders (shock wave)
• DART system
What is the Pacific Tsunami Warning System?
• 26 member countries
• when tsunami detected >100 regional centres are notified in less than 60 minutes
Indian Ocean Tsunami of 2004: Where did the earthquake occur?
• On the west side of Indonesia
Indian Ocean Tsunami of 2004: How many deaths in total?
• Deaths ranged from: 237,071 in Indonesia, 30,957 in Sri Lanka, 5,393 in Thailand, 16,389 in India, etc.
Indian Ocean Tsunami of 2004: How far away was the furthest recorded death?
Indian Ocean Tsunami of 2004: How high was the wave run-up?
• Some places recorded at greater than 25 meters
Indian Ocean Tsunami of 2004: What was so significant about the earthquake?
• Longest known earthquake rupture (>1300 km in length & 240 km in width) and largest in over 40 years
• The rupture moved at 2-3 km/s northward like a zipper
• Energy released from quake equals energy used by the USA in six months
• Shallow earthquake (30km)
• Felt most in Indonesia
Indian Ocean Tsunami of 2004: What about the aftershocks?
• Over 150 >5 magnitude earthquakes for weeks after
Indian Ocean Tsunami of 2004: What were the economic damages?
• Immediate damage: >$10 billion USD
• Reconstruction costs: >$15 billion USD
• Regional development: by many estimates, development in most affected countries has been setback by a generation
Indian Ocean Tsunami of 2004: Where did most of the aid come from?
• 45% from governments ($6 billion)
• 38% from private individuals/companies ($5.1 billion)
• 17% from international financial institutions ($2.3 billion)
Indian Ocean Tsunami of 2004: What kind of environmental damage was there?
• Coastal: dunes & beaches, coral reefs, mangroves, salinization of land
• Regional: uplift and subsidence
Why are atmospheric hazards so important?
• They are the most commonly felt hazards
Atmospheric Hazards: What are a few of them?
• Hail, lightning, rain, wind, freezing rain, snow, sever cold/heat, fog, etc.
What is the distribution of atmospheric hazards?
• Atmospheric hazards are felt everywhere, but not all locations experience all phenomena
Atmospheric Hazards: What does it depend on?
• Temperatures, heat (energy), moisture, proximity to water, weather fronts, etc.
Damages: What was the hail damage and deaths?
• $2.8 billion yearly
• 2 deaths in the last 200 years
• 110 deaths per year
Extreme heat in Europe 2003?
• 35,000-50,000 deaths (record temperatures)
• 8 countries
• Timing was critical: vacation month
• staff shortages in care facilities, families not checking on elderly, physicians on holidays, etc.
Winter Storm Hazards: What are some types?
• Major snowfall: >25 cms in 12 hours
• Blowing snow: winds of >30 km/h & visibility <800 meters for >3 hours
• Blizzard: sustained winds >40km/h & snow for more than 4 hours
• Lake effect snows: cold air moving over warm water mass, often >20 cm in 12 hours
• Snow squall: >15 cm in less than 12 hours & <400 m visibility for >3 hours
• Ice storm: >6mm of ice coating
Hazard Components: What are some components to winter storms?
• Cold, weight of snow/ice, reduced traction, wind, reduced visibility, snowmelt (flood), etc.
What was the most costly Canadian disaster ever?
• Quebec Ice Storm of 1998
• >80 hours of freezing rain
• Houses without electricity for 5 weeks (120,000 km of downed power lines)
• >$5 billion damage
• infrastructure, property damage, forest resources, lost productivity (20% of employed Canadians lost work)
• 45 deaths in both Canada and US
Difference between economic damage and human loss: Hail? Lightning? Freezing Rain? Snow? Sever cold/heat?
• Hail: economic loss, not very many human lives being lost
• Lighting: both human and economic damage
• Freezing rain: more of an economic issue
• Snow: more of an economic issue
• Sever heat/cold: loss of human lives is a large concern, not much of an economic issue
What is a complex winter storm?
• Comparable to a hurricane in scale and intensity
• Wide area of extent: different types of hazards, persistent (many days), changeable over time
• E.x.: snow, freezing rain, rain, heavy rain, flash flooding, heavy surf off the coast, tornadoes