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Hazards Test 1


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Prevention of a natural hazard from becoming a natural disaster
Do people tend to reoccupy natural disaster locations? Why?
Yes, opportunities, faith, fatalism, etc
Magnitude varies over what?
space and time
As magnitude _________, frequency __________
increases, decreases
Return Period
the number of years between same-sized events
Low-fatality hazards
Floods, tornadoes
High-fatality hazards
Earthquakes, hurricanes
Exponential Growth
Lots of population growth in a short period of time
Doubling time
The number of years it takes for a population to doublw
What is our doubling time?
53 years
What will the human population be in 2050?
9 billion
Energy Sources of Disasters
Asteroids, gravity, internal energy, the sun
Water is what kind of molecule?
How much does water expand by when it freezes?
Plate tectonics theory
epicenters are along fault lines
Divergent boundary
Two plates are pulling away from one another
Convergent boundary
two colliding plates
Transform fault
two plates slide past one another
Young spreading center and the plates involved
East African rift valley; African and Somali
Turkey is famous for what kind of fault?
What kind of fault is the dead sea fault?
What causes an earthquake?
Fault movements, volcanoes, meteorite impact, nuclear bombs, undersea landslides
What is the difference between a hanging wall and a footwall in a mine shaft?
Footwall is the one you walk on, hanging wall is above your head
Normal Fault
Looks like you could step down, the footwall rose up
Reverse Fault
The hanging wall rose up
What can P-Waves move through?
Solids, liquids, and gases
What can S-Waves move through?
Estimate of the energy release of an earthquake
Moment magnitude
Used for large or far away earthquakes-amount of movement on the fault
9 N.American earthquake regions
Pacific NW, W. Great Basin, Intermountain belt, Rio Grande Rift, Intraplate Central, Intraplate East, Hawaii
How many times did Ancient rifts occur in Central U.S?
Resistance to flow
Low viscosity?
Low resistance to flow, more fluid like
Why does magma explode at subduction zones more than spreading centers?
The magma is more viscous and the gases can't escape as easily
How is magma generated?
Lower pressure, raise tem and water content
What are some ways energy exists?
heat, light, water, electricity, chemical
1st Law of Thermodynamics
Energy can neither be created nor destroyed
Why is gravity centered in a planetary body?
That's where the attracting mass is
How old is the Earth?
4.5 billion years/4500 million years
Do all objects radiate energy?
More solar radiation in certain areas
Latent heat
Carried in water vapor, releases during condensation
principle of buoyancy
How many plates are there?
Is Iceland's boundary young or old?
Dip-slip fault
caused by a pushing or pulling force
For P waves, the greater the density and resistance, the...
greater the speed
What does S wave speed depend on?
density and shearing
What are the L waves?
Love and Rayleigh
travel through solids, faster than Raleigh
eliptical motion, moves through solids and liquids
Intensity scales were named after whom?
Mercalli and Richter
harbor wave created by earthquakes or landslides
Seismic Gap Method
predicting earthquakes based on old earthquakes
What three plates are subducting under the NA plate?
Juan de Fuca, Gorda, Explorer
Why are failed rifts hard to study?
They are deeply buried

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