Week 1 Flashcards
Lecture 1
What is the difference between the topography of a volcano on earth and on mars
- The earth’s surface is rougher as it is more dynamic - this would mean that it responds differently to the loading
- Both mars and earth is active but the level of activity is higher on earth hence resulting in eruptions
Why are there natural hazards on earth
We have physical status of water on earth. Hence, this allows for life on earth allowing the exchange of energy between different layers of the earth. This allows for the accumulation of energy.
Natural events are just different forms of energy release in a relatively short amount of time
Why is there less temperature rise in the ocean
The ocean has a higher heat capacity as compared to land. Hence harder to have a big temperature change
Change can also be due to ozone
What do you think are the reasons of COVID-19
Some viruses can be frozen in the ice sheets but due to global warming, the ice sheets melt and this results in an increase in viruses
Some examples of the southeast asia ring of fire
Java
Sumatra
Papua New Guinea
Philippines
What are some natural hazards near the ring of fire
Typhoons
Tsunamis
Earthquakes
What has been installed in Singapore and what is it’s use
seismometers
Used for finding in seismic events
these are tiny events that are often missed as they are around magnitude 1-2
Why is there an increase of hazards on earth
Due to an increase in the global population
Advanced science development - allows us to handle diseases better (thus we live longer)
The exponential growth of human technology allows for the growth of the human population
Geohazards are a significant challenge of living on a dynamic planet
Catastrophes in nature
- everyday geologic processes produce large effects
- sudden and major impact of infrequent catastrophic events
- Disruption of temporary equilibrium between opposing influences
- Large events are part of nature and can be disastrous if they affect people
What is a natural hazard
Natural process that poses threat to human life or property
What is a natural disaster
Natural event that causes significant damage to life or property
What is catastrophe
Natural event that kills or injures large numbers of people or causes extensive property damage
How does size and location affect impact of disasters
Fewer people and buildings - little damage
Heavily populated areas - catastrophic deaths and damge
More deaths result from…
Heat waves
Floods
Droughts
Dramatic hazards occur…
infrequently and in restricted areas hence fewer deaths
Why is there significant differences in fatalities from year to year
- rare and major events cause many deaths
- trends in leisure activities and safety measures affect fatality rate
- higher fatality rate in developing countries
Why is there an increase in cost of natural hazards
- more people in path of catastrophic events
- increased value of property at risk
Human impact of Natural disasters
- hydraulic fracking and wastewater disposal
- increased greenhouse gas emissions
- other human activites
- e.g effects of climate change
1. more rapid erosion of coastlines
2. extreme weather events causing landslides
3. Rise in sea levels - Development of science and technology (more data and more detailed analysis)
What is marco scope observations
More than 2000 satellites recording data
allows for alot of new findings to be made
What is micro scope observations
Can zoom into molecular scale and see the lvl of details and distribution of elements
Why do we have to predict catastrophes
to avoid them and get them out of the way
Why is it hard to predict catastrophes
- Few well documented instances of prediction
- some natural events have predictable cycles - but usually too many variables or overlapping cycles
- forecasting hazardous events might be possible in certain areas within a few decades
Predicting catastrophe
- the past is the key to the future
- refinement of past recorded experiences produces statistical forecasts
1. expressed as recurrence intervals
2. probability that a natural event of a certain magnitude will happen within a certain period of time
3. Not a fixed schedule for events - Estimating the reccurance interval
Relationship between magnitude and frequency
Magnitude of an event is inversely proportional to its frequency due to the conservation of energy
Hence resulting in numerous small events
Infrequent occurrence of major events makes them difficult to study
Relationship among the events
Some events are directly related to each other or may overlap to reinforce each other
Past events influence future events
Some events result in more rapid changes: feedback effects
Examples of feedback effects
Global warming melts artic sea ice - the darker ocean water absorbs more solar radiation than white ice causing more melting of ice
Increased cost of hydrocarbon fuels reduces usage
Mitigation
- These efforts prepare for a disaster and reduce its damage
Examples of mitigation
Engineering projects (leeves)
Government policies (zoning, codes)
Public education (earthquake drills)
Land use planning
Find out where disasters are likely to occur and restrict development there
However these planning often come in too late
- hazardous areas are already heavily populated
- regulation often ignite intense political and legal oppositions
- restrictions are viewed as infringement of personal and property rights
Insurance
To mitigate financial impact of disasters
Risk: hazard considered in light recurrence intervals and expected costs
- Greater hazards, shorter recurrence intervals - great risk
Insurance costs are actuarial, based on past experience
The role of the government
Research natural and behaviors of natural disaster e.g U.S Geological Survey - studies earthquakes, volcanoes and stream flow
National weather service - monitors rainfall and severe weather
Emergency management agency - role initially to organize relief efforts, shifted to emphasizing hazard reduction
Public education
Living with nature
Cannot change natural laws
attempts to control nature would only:
1. temporarily hinder natural process
2. divert damaging energy to other locations
cause energy to build up - resulting in more severe damage later
- must learn to live with nature and not to control it
- mitigation requires human behavior change
