Geophysics

Author Profile

Stephen K. Boss
,

sboss@uark.edu

University of Arkansas
a

University with graduate programs, including doctoral programs

Summary

This is a first course (survey) in geophysics designed for senior undergraduate geology majors at the U. of Arkansas.

Course Size:

less than 15

Course Context:

In Fall 2008, this course will become a required course for those students pursuing a BS in Geology. Prerequisites are 1) year-long physics sequence, 2) structural geology. The course has 2 x 1-hour lectures and 1 x 2-hour lab each week. Laboratory exercises emphasize basic principles of geophysics utilizing on-line data resources of many types; students must develop proficiency with spreadsheet software (MS Excel) as the semester progresses in order to successfully complete laboratory assignments. Labs emphasize manipulation of real-world geophysical data applied to geologic problems. Heavy emphasis on solid Earth geophysics (seismology, paleomagnetism) and exploration geophysics (mostly seismic, gravity methods).

Course Goals:

Students should be able to employ fundamental principles of seismic refraction to solve relatively simple geologic problems (such as derive simple crustal structure from a refraction survey).
Students should be able to recognize signatures of direct waves, reflected waves, refracted waves on seismic records.
Students should know that many applications of seismic methods utilize time versus distance plots.
Students should be able to manipulate equations governing seismic refraction and seismic reflection to create simple models of these phenomena using spreadsheet software.
Students should develop skill in manipulating spreadsheet software to solve simple geophysical problems. In addition, students should be developing their 'numeracy' in geology.
Students should be able to describe fundamental principles of Earth magnetism.
Students should be able to examine marine magnetic profile data to construct simple 'magnetic reversal' profiles.
Students should know age-depth relations of oceanic crust.
Students should be able to correlate seafloor magnetic profiles using principles of magnetostratigraphy.
Students should be know fundamental principles of Earth's gravity and why it varies globally.
Students should know how to reduce gravity data to derive simple free air and Bouger anomalies.
Students should be able to invert gravity data from Bouger or free air anomalies to actual gravity measures.
Students should be able to demonstrate their numeracy through problem solving exercises.

How course activities and course structure help students achieve these goals:

Course lectures and reading assignments are closely linked to laboratory exercises. Lecture often open with a question related to a geological problem in the form "How would you determine...". Students are encouraged to discuss exactly how one might obtain information about the Earth - what tools might be available, how measurements might be made, how data might be interpreted, etc. Lectures attempt to pose potential numeracy skills needed and instrumental measures to be made. Labs attempt to employ these numeracy skills using real or simulated data to solve simple geologic problems. Assessment of student progress is from written lab assignments and examinations throughout the semester.

Skills Goals

I believe this course does much to promote student numeracy and develop their skills using spreadsheet software (which many do not have at the outset).

How course activities and course structure help students achieve these goals:

Students cannot successfully complete the course without developing these skills. We use spreadsheet software for virtually every assignment. Assignments are structured to require increasingly complex analytical skill, building on previously practiced and learned skills.

Attitudinal Goals

Part of my intent in this course is to demonstrate the real power and beauty of math and physics applied to geology. I want students to appreciate that a small investment in numeracy can place them on a path to professional success.

How course activities and course structure help students achieve these goals:

Well, I must report honestly that I think I do a poor job of achieving this goal. Unfortunately, the majority of my students enter the course with great apprehension (I would say even loathing) of mathematics and its place in Geology. They have already been turned off physics by the undergrad physics sequence and fail to recognize the real beauty of physics and math in Geology. I don't believe I am very successful in this particular area. My students tend to hate this course because it is 'hard' and, increasingly, it seems all students want all courses to be 'easy' (if not easy, entertaining).