How is the ocean floor similar to a gigantic, slow-moving tape recorder?
In what way does seafloor spreading support continental drift?
Name and describe the three types of plate boundaries.
The lithosphere moves because of convection currents in the mantle. What causes the convection currents?
What is a rift? Give an example.
What kind of boundary separates the South American Plate from the African Plate?
What are the three types of plate collisions that occur at convergent boundaries?
What is a transform boundary?
Are folded rocks primarily the result of compressional or tensional forces?
Distinguish between anticlines and synclines.
What is the difference between reverse faults and normal faults?
Which kind of fault forms primarily from tension in Earths crust? Primarily from compression?
What happens to rock when stress exceeds a rocks elastic limit?
Where are most of the worlds volcanoes formed?
What is the source of a tsunamis huge amount of energy?
A slinky offers a great way to illustrate how seismic waves travel through Earths interior. Place the Slinky on the floor. With two people firmly holding the ends of the Slinky, stretch it out to...
Look for a very old window, and note the lens effect in the bottom part of the glass. Glass has both solid and liquid properties; in fact, it is often thought of as a very viscous liquid. Over many...
As the ground shakes, so do buildings on top of the land. It is often said that earthquakes dont kill people, but falling buildings do. Older, unreinforced brick buildings and woodframe buildings can...
The weight of the ocean floor bearing down on the lithosphere is increased by the weight of ocean water. Relative to the weight of the 10-km-thick basaltic ocean crust (density 3 g/cm 3) , how much...
If the mid-Atlantic ocean is spreading at 2.5 cm per year, how many years has it taken for it to reach its present width of about 5000 km?
The Richter magnitude scale is logarithmic, meaning that each increase of 1 point on the scale corresponds to an increase by a factor of 10 in the amplitude of the seismic waves recorded on a...
If the rate of movement along a fault is known, the amount of offset over a period of time can be calculated. The basic relationship is Rate = distance/time Movement along the San Andreas Fault is...
The San Andreas Fault separates the northwest-moving Pacific Plate, on which Los Angeles sits, from the North American Plate, on which San Francisco sits. If the plates slide past each other at a...
List the parts of Earths crust in order of generally increasing density: (a) Oceanic crust, (b) Continental crust, (c) Asthenosphere, (d) Lithosphere.
Going from slowest to fastest, rank the following seismic waves: (a) Rayleigh waves, (b) P-waves, (c) S-waves.
Earths crust and its core differ greatly in density. After a quick review of Sections 20.1 and 21.2, rank the following elements in order of increasing density: (a) Iron, (b) Silicon, (c) Nickel, (d)...
Earthquakes at plate boundaries vary in their size and destructiveness. Rank the types of plate boundaries according to increasing earthquake destructiveness: (a) Divergent boundaries, (b) Transform...
Compare the relative speeds of primary and secondary seismic waves. Which type of material can each travel through?
How can seismic waves indicate whether regions inside Earth are solid or liquid?
Consult Figure 21.37 and rank these countries in terms of earthquake frequency (from greatest to least): (a) Greenland, (b) United States (lower 48 states), (c) Indonesia, (d) Australia. Key Shallow...
How do seismic waves indicate layering of materials in Earths interior?
What does the P-wave shadow tell us about Earths composition?
What is the evidence that Earths inner core is solid?
Even though the inner and outer cores are both composed of predominantly iron and nickel, the inner core is solid and the outer core is liquid. Why?
If Earths mantle is composed of rock, how can we say that the crust floats on the mantle?
Does the fact that the mantle is beneath the crust necessarily mean that the mantle is denser than the crust? Explain.
Why is Earths crust thicker beneath a mountain range?
Which extends farther into the mantle: the continental crust or the oceanic crust? Why?
How do erosion and wearing away of a mountain affect the depth to which the crust extends into the lithosphere?
Speculate on why the lower part of the lithosphere is rigid and the asthenosphere is plastic, even though they are both part of the mantle.
Where and what is the most likely source of the energy that generates Earths magnetic field?
How did glacial striations support Wegeners hypothesis of continental rift?
Describe how the different paths of polar wandering helped establish that continents move over geologic time.
How is Earths crust like a conveyor belt?
Upon crystallization, certain minerals (the most important being magnetite) align themselves in the direction of the surrounding magnetic field, providing a magnetic fossil imprint. How does the...
What is meant by magnetic pole reversals? What useful information do they give us about Earths history?
How are the theories of seafloor spreading and continental drift supported by paleomagnetic data?
Where is Earths longest mountain range located?
Why are the most ancient rocks found on the continents, not on the ocean floor?
What kinds of plate boundaries are associated with centers of seafloor spreading?
What is the driving force for mountain building in the Andes?
At what type of plate boundary were the Appalachian Mountains produced?
Why do mountains tend to form in long, narrow ranges?
What kind of plate boundary separates the North American Plate from the Pacific Plate?
Why does granite form frequently at oceaniccontinental convergent boundaries but infrequently at oceanic oceanic convergent boundaries?
Magma is generated at divergent and convergent plate boundaries. What type of magma is dominant at each boundary? Why are they different?
How old is the Atlantic Ocean thought to be? For how many years has lava been extruding at the Mid-Atlantic Ridge?
What type of lava erupts at divergent boundaries? What type erupts at convergent boundaries?
How did the Himalaya Mountains originate? How did the Andes Mountains originate?
Lithospheric rock is continuously created and destroyed. Where do the creation and destruction take place? Do the rates of the two processes balance each other?
Subduction is the process of one lithospheric plate descending beneath another. Why does the oceanic portion of the lithosphere undergo subduction whereas the continental portion does not?
Where does most of an earthquakes damage generally occur?
What type of fault is associated with the 1964 earthquake in Alaska?
The Mercalli scale measures earthquake intensity. The Richter and seismic moment scales measure earthquake magnitude. Which scale is the more precise measurement? Why?
How do faults and folds support the idea that lithospheric plates move?
Why are most earthquakes generated near plate boundaries?
How much more does the ground shake during a magnitude-6.6 earthquake than it does during a magnitude-5.6 earthquake?
In 1960, a large tsunami struck the Hawaiian Islands without warning, devastating the coastal town of Hilo, Hawaii. Since that time, a tsunami warning station has been established for the coastal...
What is the direct source of energy responsible for earthquakes in southern California?
Reverse faults are created by compressional forces. Where in the United States do we find evidence of reverse faults?
Normal faults are created by tensional forces. Where in the United States do we find evidence of normal faults?
Strike-slip faults show horizontal motion. Where in the United States do we find strike-slip faulting?
If you found folded beds of sedimentary rock in the field, what detail would you need to know in order to tell whether the fold was an anticline or a syncline?
In an earthquake, does the release of energy usually happen all at once? Defend your answer.
Are the present-day ocean basins a permanent feature on our planet? Discuss why or why not.
Are the present-day continents a permanent feature on our planet? Discuss why or why not.
Relate the formation of metamorphic rocks to plate tectonics. Would you expect to find metamorphic rocks at all three types of plate boundaries? Why or why not?
Cite one line of evidence that suggests that subduction once occurred off the coast of California.
During an earthquake, what type of land surface is safer: rigid bedrock or sandy soil? Explain your thinking.
Where does most of Earths precipitation occur?
As water is precipitated onto the land, where does it go? Where does most of the water on land end up?
Distinguish between porosity and hydraulic conductivity.
If a hole is dug in the unsaturated zone, does it fill with water? Why or why not?
Compare and contrast the unsaturated zone with the saturated zone.
If not from the Big Bang, then where do elements heavier than helium come from?
No galaxy that has been found so far is less than 25% helium. If not from the stars, where did this helium come from?
If gravity is not a force, then what is it?
Rank the solutions in order of increasing concentration of hydronium ions, H 3 O + : (a) hydrogen chloride, HCl (concentration = 2 M); (b) acetic acid, CH 3 COOH (concentration = 2 M); (c) ammonia,...
Use the following balanced chemical equation to show that the production of 1.6 10 7 metric tons of aluminum, Al, through electrolysis each year produces about 2.0 10 7 metric tons of carbon...
Each year about 1.6 10 7 (16 million) metric tons (mt) of aluminum are produced. How many grams is this? (Recall that 1 mt is 1000 kg.)
Show that the pH of a solution is -0.301 when its hydronium ion concentration equals 2 moles/L. Is the solution acidic or basic?
When the pH of a solution is 1, the concentration of hydronium ions is 10 -1 M = 0.1 M. Assume that the volume of this solution is 500 mL. What is the pH after 500 mL of water is added? You will need...
The three chemicals listed below are all very weak acids because they all have a difficult time losing a hydrogen ion, H + . Upon losing this hydrogen ion, the central atom of each of these molecules...
Show that an aqueous solution having a pH of 5 has a hydroxide ion concentration of 1 10 -9 M.
When the hydronium ion concentration of a solution is 1 10 -10 M, what is the pH of the solution? Is the solution acidic or basic? When the hydronium ion concentration of a solution is 1 10 -4 M,...
Show that the hydroxide ion concentration in an aqueous solution is 1 10 -4 M when the hydronium ion concentration is 1 10 -10 M. Recall that 10 a 10 b = 10 (a+b) .
You can see the electrolysis of water by immersing the top of a disposable 9-V battery in salt water. The bubbles that form contain hydrogen gas produced as the water decomposes. Why does this...
A battery is made by connecting a metal that tends to lose electrons with another metal that tends to gain electrons. Two metals that make for a good battery are copper and zinc, both of which are...
Silver tarnishes because it reacts with the small amounts of smelly hydrogen sulfide, H 2 S, we put into the air as we digest our food. In this reaction, the silver loses electrons to the sulfur. You...
What happens to the polarity of oxygen atoms as they transform from molecular oxygen, O 2 , into water molecules, H 2 O?