__ 3413 Principles of
Geophysics.__ Prerequisite: Mathematics 2423; Physics 2524; or equivalent
or permission. A survey of current methods of geophysical measurements and their
interpretations. The earth's gravity, magnetic, seismic, mechanical and thermal
properties will be discussed. (Sp)

- Judson L. Ahern
- Office Hours: Energy Center Tower Room 924, by appointment
- Contact: 325-4480, jahern@ou.edu

Homework sets: 10 | 2 | 20 |

Tests 1 and 2 | 20 | 40 |

Test 3 | 30 | 30 |

Quizzes | 10 | |

Total | 100 |

Mostly open-notes problems, some closed-notes short questions. Exams are over material covered since last exam (i.e., no comprehensive final). Third exam on scheduled final exam day.

Wednesday, January 20 |
First Day of Classes |

Wednesday, March 4, 2009 |
Exam 1 (see below) |

Saturday, March 14 - March 22, 2009 |
Spring Break |

Wednesday, April 8, 2009 |
Exam 2 (see below) |

Friday, May 8 |
Last Day of Classes |

Thursday, May 14, 2009, 8-10 AM |
Final Exam (see
below) |

***on reserve, Geology Library**

**Note: "The University of
Oklahoma is committed to providing reasonable accommodation for all students
with disabilities. Students with disabilities who require accommodations in this
course are requested to speak with the professor as early in the semester as
possible. Students with disabilities must be registered with the Office of
Disability Services prior to receiving accommodations in this course. The Office
of Disability Services is located in Goddard Health Center, Suite 166, phone
405/325-3852 or TDD only 405/325-4173.” **

**Some possible Test 1 questions/problems (neither
limited to nor inclusive!):**

**Closed book, closed notes: **mass of Earth; radius of Earth; Kepler's
laws, in words; density of ocean and continental crust, mantle;
Earth's oblateness, as a fraction and as a per cent; g(r) for point mass or
radially symmetric body; U(r) for point mass or radially symmetric body;

**Problems:** orbital radius vs. period problem; planetary surface surface
temperature problem; computing **g** from U; computing U (or delta U) from
work done against **g**; escape velocity problem; g(r) inside homogeneous
planet; g(r) outside an infinite cylinder;

**Some possible Test 2 questions/problems** (* neither
limited to nor inclusive!*):

**Closed book, closed notes:** Be able to convert from m/s^{2} to mgals,
µgals, without a calculator (it's moving a decimal point); what is the
difference between absolute and relative gravity - why do we need both? What is
the difference between a stable and an unstable mass-spring system (gravimeter)?
Which do we use? What are the two ways normally used today to remove tidal
variation in gravity? Define the Standard Bouguer Anomaly in terms of observed
gravity and the various corrections (numbers not necessary - what corrections
need to be made?). How do filtering, smoothing, upward/downward continuation,
derivatives help us interpret a gravity profile or map? What is the uniqueness
or ambiguity problem in gravity (geophysics)?

**Problems:** For a simple mass on a spring, how much would an x meter
long spring change due to a y mgal change in g? Drift correction problem;
latitude, free-air, Bouguer correction problem(s); Total error due to dependent
and independent contributing errors; Given a gravity profile, draw a
(qualitative) corresponding second-derivative anomaly profile below it.

**Some possible Test 3 questions/problems (neither
limited to nor inclusive!):**

**Closed book, closed notes: Magnetics: **Similarities between grav and
mag; differences between grav and mag; What are the three parts of the Earth's
total magnetic field - describe briefly; difference between N & S mag poles for
best-fit dipole vs. N dip pole and S dip pole;

**Closed book, closed notes: Seismic:** What is the P-wave shadow zone?
where does it occur? what causes it? What is the S-wave shadow zone? where does
it occur? what causes it? Snell's law, general case, reflection,
refraction, mode conversion; plane-wave velocity of P waves, S waves; Can there
be a reflection between two layers but no refraction? How? Can there be a
refraction between two layers but no reflection? How? Can there be a reflection
and a refraction between two layers? How?

**Problems:** **Magnetics: **Convert between |F_{T}|, D, i, X,
Y, Z, H. Find inclination of the magnetic field for a dipole field for a
given magnetic colatitude. What is the strength of the total magnetic field for
a dipole field at a given magnetic colatitude (in terms of, say, B_{0}).
Assume that the Earth's magnetic field is a dipole. At what distance above the
Earth's surface is the magnitude of the field a given fraction of its value at
the surface?

**Problems:** **Seismic: ** Find velocities and depths from
refraction survey data for two layers on a half-space. Find velocities and dip
from refraction survey data for dipping layer on a half-space. Find the
reflection coefficient between two layers given velocities and densities. Will
there be a polarity reversal? Find the velocity and depth to a single,
horizontal layer using reflection times for different offsets. Given N
geophones, and the array is moved n geophone spacing each time, what fold
coverage will result? When N signals (and noise) are summed, how much is the
signal amplitude increased? the noise? What is the improvement in the
signal-noise ratio?

**Copyright 2007, Judson L. Ahern**