Gravity and Electromagnetics - Geology 438
Professor: Steve Sheriff
Grading: Based on exams, problem sets, project reports, participation
Spring 2002 - Syllabus
The Summer of Applied Geophysical Experience (Los Alamos National Lab)
The Society of Exploration Geophysicist scholarships

• 1/28/02: Mass, moment, gravity - much of it in spherical coordinates
• 1/30: A couple problems for next week, more on moment, and the Earth-Moon system.
• 2/4: Tidal friction, lunar recession, International Gravity Formula (gth), and the geoid (PNW, US, world geoid)
• 2/6: Some problems, then Free Air anomalies, Bouguer anomalies, terrain density, density from FAA
• 2/11: Terrain corrections, buried sphere (& 2 spheres), operating the Worden gravimeter, and a gravimeter assignment. Operating the CG3
• 2/13: Interpretation, ambiguity, case study-Evans, 1999, Gauss' theorem. (US Bouguer map, central Missoula Valley).
• 2/20: Topography & anomalies, observed, regional and residual (Figure 1, 2), Montana gravity file.
• 2/25: Gravity Problem, sampling, Talwani algorithm, 2D modeling with GravCadW, basin inversion.
• 2/27: Airy and Pratt isostasy, Montana's ranges & Tertiary Basins, and mountain roots.
• 3/4: Modeling, crustal thickness (NA, world, histograms), n-central MT anomalies, sedimentary basins.
• 3/6: Rocky Mountain development (P. Bird), accomodation space, uplift following erosion.
• 3/11: Problems, landscape erosion, Elev/BA profile, Hudson's Bay (geoid).
• 3/13: mantle viscosity, backstripping, flexure of the crust & lithosphere (A.Watt's)
• 3/25: Elastic thickness, flexural equation, flexure from a periodic load (here's the mathcad document)
• 3/27: More periodic load, end loads (mcad doc), elastic thickness from FAA analysis
• 4/1: Foreland basins, GPS and gravity assignment, GPS error figures (1, 2, 3, 4), PDOP figure.
• 4/3: Midterm Exam (for old exams)
• 4/8: I'm at an out of town meeting - go to guest lecture and work on gravity assignment
• 4/10: Operating the GPS unit, gravity drift corrections, gravity assignment
• 4/15: Assignment - Attend GEODAYS!; Hennes and Phillip's presentations are fair game on the final
• 4/17: How to do differential corrections, terrain corrections, etc.
• 4/22: Gravity questions/answers; electromagnetic surveys at the environmental scale
• 4/24: GPR basics, images (1, 2, 3), applications (short class, I have to leave at 3:50).
• 4/29: Setup and operation of the EM31 from GEONICS, and an EM31 assignment
• 5/1: Questions about EM31 assignment, setup/demo of the Mala Ramac GPR; EPA's GPR page
• 5/6: More GPR in the field (if the weather had cooperated - instead we combined gravity results)
• 5/8: Acquisition and Processing/visualization of GPR data
• 5/15: Take Home Final Exam is due we still meet 3:20 - 5:20; all problem sets and papers must be turned in by now.

Equipment & Procedures:

Read the Gravimeter's Scale	Calculate Drift Corrections	Gravity Flow Chart
Terrain Corrections	GravcadW	PRO-XRS GPS (from Trimble)

 

Earth Coordinate Systems	Geodetic Datums	NGS Geoid Page
GPS Overview	SEG Virtual Museum	Wolfram Resources
Representative textbooks	Society of Environmental and Engineering Geophysics	AGU Reviews of Environmental Geophysics
Environmental Geophysics at Columbia University	Keele University, UK	Boise State - CGISS
Case Studies

• The Summer of Applied Geophysical Experience supported by Los Alamos National Lab and the Department of Energy.
• The SEG (Society of Exploration Geophysicists) scholarship program.

• Exercise one covers relative versus absolute addresses and graphing equations.
• Exercise two introduces Excel's array functions for transposing, multiplying and inverting matrices.
• Exercise three uses the array functions for solving simultaneous equations and fitting lines to linear data.
• Exercise four demonstrates Excel's LINEST() function for least squares.
• Exercise five requires importing ASCII data, sorting, MEDIAN(), and AVERAGE.