1. Philosophical points of this class
Turns a natural occurring hazard into a risk
Find a way to live in these natural environments
2. Four principles of natural disasters
analyze the risk
hazards are linked
human activity influences but does not determine severity of events
3. We can take advantage of the oral history to tell us about natural hazards
An 1846 painting by the American folk painter Edward Hicks, depicting the animals boarding Noah’s Ark in
He was very religious, but also drew based upon folk tales.
4. Use aerial images to tell us where natural hazards have occurred
5. 2011 Mississippi floods
6. Geological deposits can tell us something about a given event prior to human records
7. Flood deposits from Glacial Lake Bonneville
8. Our ability to minimize the hazard depends on analyzing the risk
Perception vs. reality: what is the probability that the 100 people in this room at least 2 of you have the
EXACT same birthday?
TURNS OUT THE ANSWER IS E!!!!!!!!
Why? Because your perception iz WRONG BRAJ. Basic probability shows uz dat
Odds of a particular bday bein unique is 365/365
Odds of a second bday being unique, 364/365 (like woah)
DIS WONT BE ON DA EXAM
9. REAL risk (probability x cost) vs. PERCEIVED risk (amplified or attenuated)
Ability to recollect examples
Lack of control
10. Hazards are linked. But in what way?
What will happen to these hillsides of an earthquake occurs?
B) the river will change directions
C) land sliding on the hill slopes
D) the river will erode in certain places
Answer is C
11. Human activity influences the severity
How does the passage of a flood wave change with and without the effect of humans?
12. Which of the following is not an example of linked hazards
A) Earthquakes cause landslides B) Frequent storms cause river flooding
C) Hurricanes cause excessive coastal erosion
D) Volcanic eruptions cause river flooding
13. Once we understand hazards we can predict when they will occur again
This is the fundamental way we mitigate the damage associated with hazards
This is usually done with 3 techniques:
14. We can observe evidence of previous natural hazards and assume they will occur there again
Weakest type of prediction
Doesn’t tell us anything about when and where the next hazard will occur.
15. Statistical predictions use old data to predict future occurrences
The simplest statistical model is a linear regression
Linear regression is an equation that describes the relationships between two variables
16. Predictions from mathematical models use physical equations to forecast when what will happen
Strongest type of prediction
Mathematical models take equations that approximate real world phenomenon and forecast what will
A model we are all familiar with: A=P(1+r/n)^nt
Compounding interest model The Tohoku earthquake offshore of Japan caused a tsunami. How long wi
ll it take for the tsunami to reach San Francisco?
A) 30 mins
B) 1 hour
C) 3 hours
D) 5 hours
E) 10 hours
Predictions are dangerous
Scientists have GREAT POWER and must use it carefully
A hasty warning can significantly disrupt the economy
But, often times even a thoughtful warning can be poorly received.
By all account Irene was going to be a dangerous storm, and NYC authorities handled the situation
Yet, people were still upset
To counter this we need to help people understand the challenges
Origin of the Universe: the big bang theory
I. Hubbles Law: Galaxies are receding from us at a speed proportional to their distance
• i.e. farther away are moving faster
II. Big bang happened about 15 million years ago based on 2 pieces of evidence. The first is Hubbles law
that says galaxies are moving away from us.
III. 2 line of evidence: a calculation from the expansion of the universe. After the expansion the universe
began to cool which allowed it to settle into elementary particles. Smaller than an atom. • Have not been able to capture it, it’s just a theory for now.
• These particles collide, stick together to form protons and neutrons. Fundamental component
of atoms. Hydrogen can be formed from this
Birth of the Solar System and Earth
I. A flat, rapidly floating disk forms. The matter concentrated at the center will become the protoSun.
II. The inner planets are small and rocky.
III. The giant outer planets are gaseous, with rocky cores.
IV. Most of the heavier elements exist in small (inner) planets.
V. Internal structure of the Earth: Densest materials sunk to inner core.
c. Liquid iron outer core
d. Solid iron inner core
a. Continents = granitic
b. Oceanic crust = basalt
a. Ironrich silicates
VIII.Basalt, granite, oceanic crust, continental crust
a. Oceanic crust: more dense compared to the continental crust. Lays on bottom of the
ocean, much lower than continent obviously.
b. Continental crust: less dense, floats higher on the mantle
IX. Mantle: mostly solid, ironrich silicates X. Composition of the whole earth
a. Most abundant = Iron
XI. Drilling a hole
a. Deepest well on land – 15km
b. Drilled by Soviets
c. Bottom hole temperature = 190c
d. Cost > $100 million
e. Stopped because of high cost.
XII. Analyzing Volcanic rocks
a. Can look at different materials under the volcano
XIV.How do we know the age of the Earth?
a. Radiometric dating of meteorites found on Earth, and rocks brought back from the moon
(4.6 billion yrs. Aprox).
b. Oldest rocks on earth aprox. 4.0 billion yrs.
c. Early Earth was very hot, high heat flow, raid degassing (volcanism), intense meteorite
I. Important for modern world economies
II. Important for human history
b. Iron c. Gold
e. Other gems
III. All rocks on earth are made from natural elements on earth▯element from periodic table
V. Atom (smallest particle)▯nucleus, protons (+), neutrons (o), electrons ()
VI. Elements cant be broken down
VII. 8 elements make up 98%of geospheres mass
I. Isotopes are “nuclides” of a single element that have different atomic weights
II. A “nuclide” is any distinctive type of atom
III. “Stable” Isotopes do not decay radioactively
a. Spontaneous process where on element▯another by ejecting a mass.
IV. Isotope: same type of element that have different weights
Isotopes of Hydrogen
I. 1H, 2H, 3H, 16O, 17O, 18O
18.O: 0.20% I. Ion = charged particle
II. Cation = positive charge (lose electrons, i.e. Fe+2)
III. Anion = negative charge (gain electrons, i.e., O2)
I. Ionic bonding
a. Sodium▯chlorine atom=NaCl
b. Sodium loses one electron▯electrical attraction▯chlorine acquires it.
II. Covalent Bonding
a. Carbon atoms are arranged in a regular tetrahedral structure
b. Carbon atoms share electrons between atoms.
III. In general covalent bonds are stronger than ionic bonds
I. A naturally occurring solid, crystalline substance, generally inorganic, with a specific chemical
II. Consists of one or more elements
III. Most common rock forming elements (table 1.2).
I. Color: clear, white, gray or pink
II. Habit: 6sided prisms III. Hardness: 7 (Moh’s scale of 110)
IV. Fracture: conchoidal
V. Occurrence: continental crust, sediments
I. Two types:
Plagioclase (Na, Ca)(Si, AL)4O8
White, gray, pinkish
2 cleavages at 90o
Cleavage: tendency to split along structure planes
Feldspars chemically alter to produce clays and micas
Clays have a layered atomic structure, not strongly bonded. Water can occupy space in the structure.
Some clays expand when wet and contract when dry, thus making poor foundations.
Mincas are silicate materials whose internal structures include a plane with very weak bonds. They easily
break (cleave) into sheets along this plane. Biotite (dark mica) is an ironbearing mineral. Muscovite
(silvery minca) is potassiumrich
I. Fe and Mg (similar in size, 2+ charge) – can substitute in mineral structures
Metamorphic rocks I. Schist: has foliation, meaning minerals are platy (e.g. mica) and parallel. The surface has a “sheen”.
(Forms from shales, sandstones , basalts, etc…)
II. Gneiss: has bands of differentiated minerals, often ery deformedin other words, squiggly. (Forms
from granite, sandstones, etc.)
III. Marble: metamorphosed limestone.
IV. Metamorphism: requires higher pressures and/or temperatures than lithification
Plate Tectonics: The Modern Theory of the Earth (Part 1)
I. What is plate tectonics? How does it work?
II. History of a scientific revolution
a. Early thoughts
b. “Continental Drift”
c. Discoveries on the sea floor
d. Putting it together
III. Plate Tectonics: the theory that proposes that Earth’s outer shell (lithosphere) consists of individual
pieces (plates) that are mobile, thereby interacting in various ways to produce earthquakes,
volcanoes, mountains, vasins and the crust itself
IV. Plate tectonics explains: broad spatial patterns and frequencies of hazards (e.g earthquakes and
volcanoes) and resources (e.g. mineral deposits, oil, reservoirs, geothermal fields).
V. Lithospheric plates
a. 14 big ones, 38 small ones (microplates)
VI. Different plates move at different directions at different speeds
a. Velocity can be measured. Generally <10 cm/yr
b. Note: motions are relative to the Antarctic plate. All GPS motions are relative to something
(i.e., reference frame), which we assume to be fixed).
VII. Lithosphere vs. Crust
a. Mantle is brittle (will break when too much force is applied). b. Lithosphere (most solid) vs. Crust (deeper aka increasing temp and pressure
I. Continents expand by adding new lands along their margins
II. Shield areas: tracts of ancient (>billion yr. old)
a. “roots” of ancient mountains
b. metamorphic rock, low relief.
c. Very stable – low risk of geologic hazards.
Alfred Wegener (18801930)
I. German meteorologist and Arctic explorer
II. Scientific revolutionary▯continents move!
III. Scientific outcast▯turns out science “moves” too!
Wegener’s “Continental Drift” hypothesis
I. put forth in The origin of Continents and Oceans
II. Five lines of evidence that continents had been connected as one supercontinent, Pangaea, until
the Mesozoic (25065 million yrs ago)
III. Pangaea broke up and the continents drifted to current positions by “plowing” through oceanic
Wegener’s lines of evidence
I. Fit of the continents II. Records of glaciation
III. Distribution of equatorial climate belts
IV. Distribution of fossils: mesosaurus, lystrosaurus, cynognathus, glossopteris.
V. Matching geologic units
Wegener’s tragic end
I. Died on an expedition to Greenland (1930)
II. Never saw his idea become the foundation for plate tectonics