Midterm 2 covers the materials in Lectures 10-19. The format will be the same as was the first midterm.

The following chapters will be covered on Mid-term #2
8:Earthquakes
Interlude C: Earth’s interior
2: Plate tectonics
9: Mountain Building
Interlude D: Geologic Time and Earth History
Chapter 10: Geologic Time

Chapter 11: A Biography of Earth
Chapter 12: Energy and Mineral Resources (Won't be on exam)

We spent some parts of lecture talking about science that was not covered in the text book. I would like you to be familiar with those subjects as well. Here is a list of topics that I discussed, or are discussed in the book, from which I might pull questions:

Chapter 8:
Earthquakes: Focus and epicenter
Elastic rebound theory for earthquakes
elastic (recoverable) and inelastic (unrecoverable) stress
P, S and surface wave properties (relative speed, wave behavior, where they occur on or in the planet)
What happens to seismic waves as they pass through materials of different densities?
What is the Benioff-Waditi zone? How does its steepness affect the distribution of earthquakes relative to the ocean trench?
How a seismograph works
Note that a 1 second delay between the first arrival of P and S waves equates to a 15 distance to the hypocenter.
How is the Richter magnitude of an earthquake calculated? How does a M6 compare with a M7 earthquake in terms of amplitude of shaking and energy released?
Moment Magnitude and Modified Mercalli intensity scales- what does each represent?
Refraction of waves (what do they bend toward, and why? Remember water waves approaching shore)
Liquefaction- why does it occur?
Tsunamis- what generates them? what are the warning signs prior to a tsunami?
Layers of Earth’s interior from seismic waves- separated based on the composition of earth (three main layers) and based on the physical properties of the major layers (five main layers).
Seismic wave shadow zones- why do they occur?
Faults- hanging wall, foot wall, strike, dip
Fault displacement- strike-slip, dip-slip normal, dip-slip reverse (aka thrust)
How do you note the slip direction (left- or right-lateral displacement) on a strike-slip fault?
Know the primary stress that controls displacement for each type of fault (for perspective recall the sense of displacement on the fault relative to a constant stress- the influence of of gravity).
Which kind of fault will cause weak earthquakes? Strong earthquakes?
With respect to California earthquakes, how has the Sonoma State University area fared during seismic events, and what is expected from future events?

San Andreas Fault: What type of fault is it? What is the sense of motion along this fault? What caused it to form (recall collision of N. American plate with Pacific Ocean spreading ridge, and the cartoon that shows its growth through time). What is/was the Farallon Plate? What type of plate tectonic boundary existed along the west coast of central California prior to development of the San Andreas Fault?

What are restraining bends and releasing bends? What kind of fault do they occur on? What topographic features would you expect to see at each? Where is an example of each of these in California?

Ch. 9: Mountain building
Plate tectonic boundaries- convergent (collisional) divergent (extensional) and transform (translational). Note which one causes destruction of crust, creation of crust, or conservation of crust. Note the fault types (normal, reverse, strike-slip) that occurs at each.
Note that mountains can form at each type of plate tectonic boundary, but the mountains will assume different shapes and thicknesses (e.g. Basin and Range = normal faulting, Himalaya = thrust faulting, Transverse Range = restraining bend in strike-slip faulting)
Isostasy- know the meaning of the term and know what it means for mountain ranges.
Folds: Anticlines and synclines…which will trap oil? Which type of faulting area folds associated with?

Interlude D: Geologic Time and Earth History
What are the conditions necessary to preserve fossils?
What are the different types of fossils?

Ch. 10 Geologic time
Radioactive dating- half life, exponential decay, parent and daughter isotopes
What happens to an element that undergoes radioactive decay (they change into different elements)

Relative age dating: All the physical principles for assigning relative ages (unconformities, uniformitarianism, original horizontality, superposition, cross-cutting relationships, inclusions, fossil succession.

Geologic Time Scale
Precambrian Eon- 88% of Geologic history. The Hadean, Archean and Proterozoic Eras

What are the main Eras of the Phanerozoic Eon? What are the ages of the Paleozoic-Mesozoic, and Mesozoic-Cenozoic Boundaries?

Ch. 11: A Biography of Earth

How did Precambrian atmosphere differ from the modern atmosphere?
Banded Iron Formations- How long ago? What does their presence tell us about the Earth?
Snowball Earth- how does it compare to the ice age that ended 12,000 years ago?
How has the Cenozoic Era climate changed from the climate of the Mesozoic Era? How has the last 3 Million years of climate differed from the rest of the Cenozoic Era?
In a general way, how has the continent of North America changed position on Earth over the last 700 Myr?

Chapter 12: Not covered.