ES 10 Geologic Principles;	Test 2;		November 15, 1994;	Alfred Hochstaedter


1. a) (5 pts) What causes a stream to be either braided or meandering? Where applicable, be sure to
include the concepts or roles of gradient, discharge, load, and the resistance to erosion of the river
banks in your answer.



b) (5 pts) In order to continue your answer you draw a meandering stream, labelling the thalweg
(i.e., the region of greatest depth and velocity), point bar deposits, and regions of greatest bank
erosion. Also show how your meandering stream might evolve to form an oxbow lake.



c) (3 pts) How much of the EarthÕs total fresh water, not including that contained in the polar ice
caps, is groundwater?2. a) (4 pts) What does the coefficient of permeability represent? What are its units? What are
some typical values? How does it influence discharge?


b) (4 pts) What is porosity and how does it differ from permeability? 


c) (4 pts) What is the hydrologic gradient? What are its units? How would you determine a value
in a real-life situation? How does the hydrologic gradient influence discharge?


d) (5 pts). Draw a cross section that relates geology to ground-water hydrology to explain the sort
of setting your friends will need to find in order to narrow down the places they will look for an
artisan spring or well. Using your drawing, explain where an artisan spring or well might be found
and why. In addition to more obvious features, please be sure to include the potentiometric surface
and recharge region in your drawing.

3. a) (3 pts) How do waves form in the first place?


b) (3 pts) Why do waves ÒbreakÓ?



c) ( 4 pts) What causes wave refraction, and what are at least two examples of the geological
effects?


d) (3 pts) How do waves cause longshore drift to occur?


e) (5 pts)  Beach morphology (i.e., shape) can often be described as the result of competing forces
between tidal forces and longshore drift. This is especially true at the mouths of lagoons or rivers.
Please give one example of this. Describe or draw a beach and explain which aspects of its
morphology are due to longshore drift and which are due to tidal forces. Use a diagram if you like
to make your answer more clear. 

4. a) (5 pts) What, exactly, do stress and strain measure, and why do we plot them against each
other? What are their units?



b) (4 pts) Label which of the following diagrams refers to brittle deformation and which indicates
ductile deformation. Also, list and briefly explain or provide examples of the four factors that
control whether ductile or brittle deformation will occur.

c) (5 pts) Complete the following table:

kind of stress	compressional	extensional 	shear
picture of typical fault
in this environment






			
name of this kind of 
faulting			

d) (5 pts) The following is a map view of a plunging anticline. Label the limbs and axis. In what
orientation would you expect to find axial plane cleavage? Which direction is the anticline
plunging? Where are the youngest rocks? Where are the oldest rocks?

5. a) (5 pts) What causes EQs? What role does elastic rebound play?



b) (4 pts) What is the difference between magnitude and intensity? What do each of these depend
on?


c) (4 pts) Following is the list of possible building locations. Please list the specific seismic
hazards (if any) that exist at each location with respect to the San Andreas and related faults along
the Central Coast of California.

In downtown Santa Cruz, equidistant between PergalesiÕs and the Java House.

In the Santa Cruz Mountains, on a steep slope just above the reach of the summer fog.

On the UC Santa Cruz campus, using the Great Meadow Quartzite as a foundation.

On the westside, very near EmilyÕs Bakery and on the Highway 1 Terrace.

6.a) (4 pts) Note the steep cliffs along this river that has a meandering shape. Starting with the
deposition of sediments, what is the Earth history of this place?

b) (4 pts) This is a strangely symmetrical spot. Starting with the deposition of sediments, what is
the Earth history of this spot, and what is this structure called?

c) (4 pts) Never mind the rock types here, but why is this valley so U-shaped? What happened
here?

d) (4 pts) Note the stepped regions of flat topography above the coast. What are these called? How
do they form? Is this an emergent or submergent coastline? To what present-day feature -- of
which nice examples occur at Natural Bridges -- can these be related?

e) (4 pts) What is this linear feature? If it is a fault, specifically what kind is it and which way is the
offset?