A Fragile System?
A Fragile System?
Natural cataclysmic events affect the Earth every day, and are a normal part of the
Earth-ocean-atmosphere system. However, these same events (landslides,
earthquakes, hurricanes, tsunami, etc.) can kill people or reduce the quality of life. This
dichotomy motivates the title for this Module: Is the Earth a fragile system?
To address this question, you start by reviewing the metrics used to describe our world.
You next look at the materials that make up the Earth, ocean, and atmosphere. Natural
processes can be disasters because of their tremendous energy release, so you will
review the types of energy. Some disasters such as earthquakes and tsunami
propagate as waves, which you will study. With this background, you will examine the
relationship between population growth and the societal impact of natural disasters, and
make your own decisions about whether the Earth is a fragile system.
INSTRUCTIONS and QUIZ
Study and make notes based on the online course material and the textbook reading
assignments, and read the commentaries that follow. The review questions will allow
you to assess your understanding of the key concepts.
This Module will be covered in the Fragile Systems Quiz. Consult the FAQs for
information on taking the Quizzes.
The goal of this Module is to prepare you for the Modules that follow; namely, to help
you understand the basic concepts used to describe different disasters, and to help you
put disasters into perspective. After you complete this Module you will be able to:
A. Describe the physical world:
1. Physical units and their typical magnitudes.
2. Layers within the atmosphere, ocean, Earth.
3. Chemical nature of elements and crystals; Behavior of solids vs. fluids.
4. Factors causing motion and change.
5. Energy types, conversions, sources, and concentration processes.
6. Wave types and metrics; Turbulence.
7. Disaster scales and return periods.
8. Population growth, doubling time, and the future.
Page 1 of 54