Challenge of Natural Hazards Flashcards
Natural Hazards, Tectonic Hazards, Weather Hazards, Climate Change
Natural Hazard: A threat…
A threat (whether natural or human) that has the potential to cause loss of life, property damage, injury, socio-economic disruption or environmental degradation. (eg, Hurricane Haiyan, Mt St Helen eruption)
Tectonic hazards (caused by movement of plates)
Earthquakes, volcanoes, tsunamis
Biological hazards (involves living organisms)
Forest fires
Atmospherical hazards (caused by changes in the atmosphere)
Tropical storms, blizzards, tornadoes
Geomorphic hazards (occurs on the earth’s surface)
Floods, landslides (can also trigger other natural events)
Hazard risk (factors that affect response)
- Experience
- Education
- Material well-being (wealth)
- Personality
- Age — children, elderly, pregnant women
- Personality (leader/follower)
- Emergency response
- Infrastructure
Hazard risk (why people live near areas with tectonic activity)
- Fertile soils —> successful farming
- No choice —> poverty (no other options)
- Economic activity (rich in resources, tourism growing in volcanic areas)
- Perception of risk —> natural hazards are rare and moving away is too much of a struggle
- Investment —> developed cities in HICs (eg, Los Angeles) have earthquake proof buildings
- Early warning systems —> satellites and technology can detect the arrival of a natural hazard
- Geographical inertia —> families lived here, coupled with rapid population growth in LEDCs
- Hazard management —> technology and infrastructure designed to have less impact from natural hazards
Key factors affecting hazard risk
- Vulnerability
- Population density — (higher population density, more -people are vulnerable)
- Capacity to cope — (HICs often better equipped - build defenses, evacuate quickly, quick emergency response, swift medical assistance, rebuild quickly)
- Level of preparation
- Hazard type — (some can be predicted - tropical storms - others cannot - earthquakes)
- Hazard frequency — (many earthquakes make it hard to rebuild quickly and great damage to economy)
- Nature — (more severe natural hazards cause greater impacts)
Tectonic hazards occur…
Tectonic hazards occur on or near plate margins, near the Pacific Ring of Fire, near coastal areas, the western coastline of North and South America, and south and eastern Asia
Layers of the earth: The Crust
- 80-40 km thick, less than 1% of the earth
- Composed of igneous, sedimentary and metamorphic rock
- Divided into tectonic plates —> destructive and constructive plates (oceanic and continental plates)
Layers of the earth: The Mantle
- 2900 km thick, 84% of the earth
- Composed of magma
- 500-900ºC
- Convection currents cause the plates in the crust to move
Layers of the earth: The Outer Core
- 2300 km, 15% of the earth
- Composed of iron and nickel
- 4000-5000ºC
Layers of the earth: The Inner Core
- (Radius) 1220 km, less than 1% of the earth
- Composed of iron and nickel, high pressure causes iron and nickel to remain solid
- 5000-7000ºC
Oceanic Crust is…
thin and more dense
Continental Crust is…
thick and less dense
Destructive Plate Margin
Plates move towards each other
Oceanic plate — Continental plate
Oceanic plate (more dense) subducts under Continental plate (less dense); oceanic plate melts and pressure builds from friction between two plates; eg, Andes
Earthquakes and Volcanoes occur
Collision Plate Margin
Plates move towards each other
Continental plate — Continental plate
No subduction occurs; plates of equal density crumple up to create fold mountains; eg, Himalayas
Earthquakes occur
Conservative Plate Margin
Plates move alongside each other
Plates can move in opposite directions or same direction at different speeds; pressure builds over a long period of time; eg, San Andreas Fault (same direction, different speeds)
Earthquakes occur
Constructive Plate Margin
Plates move apart
Gap created where magma rises; creates new oceanic floor or volcanic islands; eg, Iceland, Mid-Atlantic Ridge
Earthquakes and Volcanoes occur
Primary Effects
First/direct impact of a natural hazard on the population (people and property)
Secondary Effects
After effects of a natural hazard on a longer timescale
Immediate Response
How people react as the event is happening
Long-Term Response
How people react in the days/weeks/months after the event has happened
HIC
High income country — GNI is over $12,000 per person
LIC
Low income country — GNI is under $12,000 per person
Planning
Food & medical supplies; Evacuation center; Land use zoning; Education —> earthquake drills, TV adverts; Emergency & first aid kits; Good communication systems