# Earth’s Interior And Geophysical Properties Geology Discussion Help

Note 1: Answers to “short-answer” questions should be no longer than a few sentences.

Note 2: As per instructions (“How to Turn In Assignments”)– make sure that you copy this assignment into a MICROSOFT WORD DOCUMENT, and place your answers below each question…. save it on your computer, and then UPLOAD the assignment using the “SUBMIT ASSIGNMENT” button!

1. Once it detached from Pangaea, did India move northwards relatively rapidly or relatively slowly (compared to other plate motions)
2. Which separated from Pangaea first, North America or South America

3. Which of the following rates represents a geologically typical plate motion velocity?

.001 cm per year, 5 cm per year, or 100 cm per year
(This is discussed in your textbook; however, you could calculate an average spreading rate for North America moving away from Africa, based on the distance between the two continents and the information in the video on timing of separation.)

4) When did Pangea begin its initial break-up?

5) Consider the Velocity of P waves in the deep earth.
Recommended to review the following diagrams– Figure 2.2, “a” and “b” AND Figures 2.7, 2.8, and 2.9.
Look at the way in which P-waves bend when they reach the outer core.
Compare the P-wave seismic velocity of the lower mantle to the P-wave seismic velocity of the outer core.

6) We think of compasses as pointing in a 2-dimensional “horizontal” framework. One end points north and the other end points south. But the earth’s magnetic field also has a vertical component, called “dip.” (See the section, in Chapter 2 titled “Earth’s Magnetic Field”). A compass needle that is not constrained to a horizontal plane will also have a “dip” to it.
QUESTION: How does the “magnetic dip angle” vary with latitude? (HINT: Think about where on the earth the magnetic field lines are vertical and where they are horizontal, relative to earth’s surface.

7) The Mohorovicic Discontinuity (Moho) separates which of the following:

A) Mantle/Crust
B) Lithosphere/Asthenosphere
C) Core/Mantle
D) Outer Core/ Inner Core

AND, the most important part of this question!—
QUESTION– Since no one has ever drilled down to the MOHO, How Do We Know where the MOHO is located, or that it even exists??

8) Doing science involves a lot of stuff. But which of the following is the BEST description of the “scientific method.”
(Sure, none of these are perfect descriptions, but one is vastly better than the others!) Explain your answer.

A) Collect samples—make measurements on the samples (with scientific instruments)—then go back and make more precise measurements.
B) Come up with a rational and logical way that the world works—debate your model with others—decide on which model seems most reasonable based on these debates.
C) Observe the world—make a model about how it works—test the model.

9 Watch the Video called “What is Science”…
I love technology—from climbing ropes to contact lenses to the 30 million dollar jet that I fly for United Express (as you’ll see on my instructor bio, my “other job” is an airline pilot). Most people agree that when science creates useful technology, science is doing a great job!

I’m thinking about writing a grant proposal to the National Science Foundation (which has an approximate 2016 budget of about 8 billion dollars)—I think it is time that we should drill down to the MOHO. This will cost NSF somewhere around 500 million to one billion dollars.

Do YOU that this is a good expenditure of NSF money? Why? Why not?
(Credit for this answer is based on your ability to write something intelligible, rational, and logical.)

10) Read about the ASTHENOSPHERE. Make sure you understand what it is, and where it exists!
We think that there may be a tiny amount of molten rock in the asthenosphere (“small degree of partial melting”) but as a whole, the asthenosphere is not molten.
How far down in the earth do you have to go in order to find a completely (fully) molten zone?