Introduction to Geophysics

Michael John Harris
,
harrismj@jmu.edu

James Madison University
a
Public four-year institution, primarily undergraduate
.

Summary

An introduction to the theories of geophysical methods, concentrating on shallow-level and environmental issues. Gravity, magnetics, electrical resistivity, IP and SP measurements, seismic refraction and reflection, GPR. Most instruments will be demonstrated and used in field situations

Course URL:
Course Size:

less than 15

Course Context:

This is an upper division elective course in the B.S. Geology Major and a potentially required course in the B.A. Earth Science Major (either Geophysics or a second Physics course). Pre-requisites include one calculus course and one physics course. The course consists of three lecture hours and two lab hours, with the lab being fieldwork intensive.

Course Goals:

  • Students should be able to operate many different, modern-technology geophysical field instruments.
  • Students should be able to understand the theory behind how each geophysical instrument operates.
  • Students should be able to interpret, to a first level, geologically, the collected field data from the instruments in goal one.
  • Students should be able to evaluate the most efficient geophysical method or methods for a particular geologic problem.


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

JMU presently has modern instrumentation for magnetics, electrical resistivity, IP and SP measurements, seismic refraction and reflection, and GPR field work. Due to time and weather constraints, most lab time is devoted to collected field data on the local campus. Data corrections and interpretations are worked into the lectures. Homework calculations followed by class discussions provide some assessment of whether the goals were achieved. Mid-term and final exams also have practical questions to further evaluate the understanding of the theories and uses of the instruments.

Skills Goals

  • formulate a field work session before going into the field, noting field area size, a project plan, potential problems with nature and humans, time constraints
  • quantitative abilities, hands-on and software-instrument- specific related
  • oral communication through discussing field data, plus presentation of other researched journal articles
  • all field work is group oriented with between 2-4 people, sometimes with a team leader


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

Class time stresses the theory behind an instrument, then a field demonstration is done and a project area is introduced. Students then have a week to plan on their own survey to collect the data as efficiently as possible. Following the data collection, discussion of the positives and negatives of the instrument, the survey and the data interpretation ensues. Ideally new problems arise during the next instrumental project, and the old problems are resolved.

Attitudinal Goals

  • building confidence in geophysics knowledge
  • building confidence in doing interdisciplinary work; relating geophysics data to petrology and mineralogy, hydrogeology, structure, and anthropogenic structures and activities
  • improving on sense of healthy skepticism; ground-truth to geophysical data is often found long after the project (and student's graduation), thus understanding how the data was collected and interpreted by the students themselves, should stress the complications and error limits used in geophysics
  • improving the students' awareness of the issues of ethics in doing geophysics; with some new instruments and "blackbox" software, "even a Caveman can do it" [collect field data], however, the interpretations are much more difficult
  • increasing the students' excitement/personal wonder about learning about the Earth; field work will do that to most people


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

Geophysical field work can be collected with undergraduates and technicians, and data is later interpreted in a lab by a geophysicist, with limited knowledge of the field area. While interpretations can be formulated, sometimes anomalies are due to something in the area not seen by the geophysicist, but not thought to be a problem by the data collector. By observing, collecting, and interpreting the data a student will realize that the field is a complex environment, and while an answer could be easy, there could be several versions of one.

Assessment

Labs/field work is based on participation and involvement (partially subjective). Some field/lab-based questions are found on the mid-term and final exams. Classroom theory material are a combination of true/false, multiple choice, short answer questions. Personally I'd place lab/field work marks between one-third and one-half of the semester grade.

Syllabus:

Syllabus (Microsoft Word 30kB Jun19 07)