Hazards Flashcards
What is a Hazard?
A potential threat to human life and property caused by an event.
Becomes a hazard when it poses a threat to people.
What is a Disaster?
The result of a hazard occurring with loss of life and damage to the built and natural environment.
What are the characteristics of hazards?
- Clear origins and effects
- Short warning times
- Involuntary exposure
- Most loss occurs immediately after the event
- Requires emergency response
What are the three types of Natural Hazards?
GEOPHYSICAL- Hazards caused by land processes i.e. earthquakes and volcanos
ATMOSPHERIC- Caused by atmospheric processes i.e. tropical storms and wildfires
HYDROLOGICAL- Caused by water bodies and movements like tsunamis and floods
What’s the difference between risk and vulnerability?
Risk- The exposure of people to a hazard presenting a possible threat to life, possessions, and the built environment.
Vulnerability- The potential for loss of life and possessions, varying between social groups, locations, and timescales.
Why do people live in hazard- prone areas?
- Low perceived risk
- Lack of alternatives
- Risk levels change over time
-Benefits outweigh costs - Family history
- Tourism income
- Scenic views
- Volcanic soil is fertile
What are the three hazard perception approaches?
Fatalism: Accepting hazards as natural events beyond control
Adaptation: Preparing effectively to survive events
Fear: Feeling too vulnerable to live in the area
What are the factors influencing hazard perception?
- Socio-economic status
- Level of education
- Occupational status
- Religion and cultural background
- Family and marital status
- Past experience
- Values and expectations
- Geographical stats
What are the three methods of hazard management?
Prediction: Warnings through monitoring systems
Prevention: Often unrealistic (e.g., stopping tropical storms)
Protection: Modifications to built environments (e.g., sea walls)
What is integrated risk management?
process considering all factors (social, economic and political) involved in risk management. This determines the acceptability of damage and disruption and deciding the actions to reduce and mitigate this.
What are the steps in integrated risk management?
- Identification
- Analysis of risks
- Establishing priorities
- Risk reduction
- Public awareness
- Monitoring and reviewing
Give examples of successful hazard management
Mt. Etna: Used dynamite to divert lava flows
Iceland (1978): Used dynamite to prevent lava cutting off the harbor
Give examples of unsuccessful hazard management
Japan (1995): Great Hanshin Earthquake destroyed 10,000+ buildings despite preparation
What are the steps in the hazard management cycle?
Preparedness: Education, risk assessment
Response: Immediate actions (rescue, warning, evacuation)
Recovery: Short- and long-term restoration
Mitigation: Future impact reduction via defenses & infrastructure
What does the park model show?
The park model aims to show the affects of hazards on the quality of life over a sequence of time. Factors influencing it is: The type of hazard, intensity, the built environment and economic status It shows the Relief Rehabilitation and construction overtime and how places alter from normality destruction and iporeent
What are the key hazard characteristics?
Distribution: Spatial coverage (area or location affected)
Frequency: How often hazards occur
Magnitude: Size and impact of the hazard
What is the shape of the Earth called and why?
The Earth is a geoid, meaning it bulges at the equator and flattens at the poles due to centrifugal forces.
What are the four main layers of the Earth?
Crust, Mantle, Outer Core, Inner Core.
What is the difference between the inner and outer core?
The inner core is solid (iron/nickel) due to high pressure, while the outer core is semi-molten.
What are the two types of crust and their characteristics?
Continental crust: Thick (30-70 km), Old (1.5 billion years), Low Density, Made of SIAL (Granite).
Oceanic crust: Thin (6-10 km), Young (200 million years), High Density, Made of SIMA (Basalt).
What are the two sources of heat inside the Earth?
Primordial heat (leftover from Earth’s formation)
Radiogenic heat (from radioactive decay).
What is the lithosphere and how does it interact with the asthenosphere?
The lithosphere is broken into tectonic plates, which move on the semi-molten asthenosphere due to convection currents.
Who proposed the Continental Drift Theory, and what was the key evidence?
Alfred Wegener (1912) proposed that continents were once a single landmass (Pangaea). Evidence includes:
- Fit of the coastlines (e.g., South America & Africa)
- Fossil correlation (e.g., Mesosaurus found in Africa & South America)
- Geological correlation (similar rock formations across continents)
- Paleo-climate data (e.g., glacial deposits in warm regions)
How did sea-floor spreading support plate tectonic theory?
Discovery of the Mid-Atlantic Ridge and:
- Age of Rocks: Youngest in the center, older outward.
- Magnetic Reversals: Alternating bands of rock show changes in Earth’s polarity every 400,000 years.