Final Exam held Friay, May 22 at 11:12:50 in Darwin 103.
You wll need only a blue scantron and pencil.
This Final Exam will focus primarily on the following chapters, which were discussed in class during lectures 21-27:
Ch. 13 Surface processes- landslides and mass movements
Ch. 14 Running water- streams and flooding
Ch. 16 Groundwater
Ch. 15 Oceans and Coasts
In addition, there will be several questions on materials covered in the first two midterms. These questions will be on topics that many students had difficulty with during those earlier midterms. My goal in asking those questions again is to reward students who take the time to learn the materials that they (probably) didn’t understand the first time they read or heard about it. So, I suggest that you review your first two midterms as preparation, and figure out the correct answer to questions that you did not answer correctly.
We talked about the following topics:
Chapter 13: Surface Processes: Landslides and Mass Wasting
What is the controlling force in mass wasting (answer: gravity).
What does water do to help cause mass wasting (answer: weight and lubrication).
What time of the year might you expect landslides to occur?
What is the angle of repose?
How is the strength of bedrock revealed through hillside slopes (consider Yosemite Valley versus Sonoma County)?
Are landslides a major concern for Sonoma and Marin Counties? (recall slide maps)
Why do some areas experience slides whereas others experience flows? (depends how strongly rock is lithified (glued together))
What evidence can you suggest to look for in order to determine if soil creep is occurring?
Case studies: La Conchita- How has geology contributed to the landslide problems at La Conchita? – Fault displacement, rapid uplift, weak materials, periodic rainfall;
Mt. Rainier, Washington: What is the major concern for debris flows (lahars) around the volcano? When might these occur?
Ch. 14 Streams and flooding
Salt: Concerns in agriculture and why the Great Salt Lake is salty (recall how wet western US was at the end of the last Ice Age)
Controls on streamflow: Gradient, channel characteristics, discharge
stream features: Cut banks and point bars
Younger river versus mature rivers: What does each river valley look like? (recall that young rivers are cutting to baselevel, mature rivers have reached it)
what is baselevel?
Why do streams meander? (recall the interplay of discharge and channel characteristics versus stream gradient)
braided versus meandering stream channels- why does each occur?
Braided streams and loess deposits in the Central US (1930’s Dust Bowl).
Flooding: causes = poor land use or unusual rainfall.
Unusual Western US rainfall associated with El Niño – La Niña climate cycles in the equatorial Pacific Ocean.
Chapter 16: Groundwater
Porosity versus permeability
Confined and unconfined aquifers
Sustainability of western US water usage: recall subsidence of San Joaquin Valley
What are sinkholes (karsts) and why do they occur?
What time during the year are sinkholes most likely to form (recall that the water tale is dynamic- it changes throughout the year)?
How do wells affect the water table if: water is pumped slowly? If water is pumped quickly? What is the consequence of water being pumped too quickly (compaction of the aquifer and subsidence)? Recall that this is what has happened to the southern part of California’s Central Valley. Is this subsidence reversible by injecting water back into the aquifer?
Ch. 15 Oceans and Coastlines
Can you label the different parts of a passive continental margin? (e.g. shelf, slope, rise, abyss).
What are the different parts of a continental margin (shelf, slope, rise, abyss)?
What are the diagnostic features that distinguish passive from active continental margins? (e.g. type of fault, seismicity, accretionary wedge, etc.)
What’s bathymetry and how is it measured today? How is this method possible?
Thermohaline circulation- the way that the ocean transports heat around the planet.
Atmosphere circulation: Know the pattern that airs flows at ground level from the equator to the North Pole.
Note that rising air causes the air to expand, which cools it, and cooling causes the air to become saturated with water vapor, so it rains).
Coriolis effect- what direction does it “bend” the wind in either hemisphere?
Note that Coriolis forcing is the reason that air moving from the equator to the pole doesn’t make it there easily; the air has to rise and descend in the atmosphere twice before it completes the trip.
What drives oceans’ surface currents (e.g. what direction do currents flow at the equator? How about the direction of flow around gyres (large circulation loops) in the Northern Hemisphere or Southern Hemisphere?)
What are gyres?
How does formation of sea ice do change the sea water beneath the sea ice?
What drives deep ocean currents (thermohaline circulation)?
What happened at 8200 years ago to the Thermohaline circulation?
Waves- crest, trough, wavelength, wave height
oscillatory motion of water waves (transfer energy, not material, across the ocean).
Why does wave motion decrease with depth?
At what depth does a wave “feel bottom”? What does this interaction with the seafloor do to the speed of the wave?
How does the shape of the coastline affect the focusing and divergence of wave energy (i.e. headlands vs. bays)? Recall refraction.
Longshore Transport- what are the factors that cause sand to migrate down current? (recall the competing forces that affect the landward trajectory and the seaward trajectory of a particle being moved down the shoreline).
Rip currents- What are they and how do you get back to shore if you get stuck in one?
Coastal landforms: Depositional (due to beach drift)
Coastline protection- groins, jetties, sea walls, breakwaters, beach nourishment
West Coast and East Coast problems with coastline protection (e.g. tectonics, sediment starvation, barrier island migration, subsidence)