GEOE 324 Engineering GeophysicsLecture Notes, January 17, 2008 Introductions Course information Goals of the course Grading, exams, term paper Important dates

Lecture Notes, January 22, 2008 Introduction to Geophysics • What is geophysics used for?• What is geophysics?• Heterogeneity• Define objectives• Limitations Lack of contrast Resolution Noise Multiple methods

Lecture Notes, January 24, 2008 Exploration With Gravity Gravitational Acceleration Measuring Gravity • Relative Measurements Pendulum Gravimeter • Absolute Measurements• International Gravity Standardization Net 1971

Lecture Notes, January 29, 2008 USGS Gravity Web Site for SD • http://pubs.usgs.gov/of/2002/ofr-02-0341/ Adjusting Observed Gravity • Variation As A Function Of Latitude• Correcting For The Latitude Effect• Elevation Corrections The Free-Air Correction The Bouguer Correction

Lecture Notes, January 31, 2008 • Elevation Corrections The Bouguer Correction The Terrain Correction The Isostatic Anomaly • Field Procedures Base Stations Elevations and Horizontal Positions Reduction Densities Survey Procedure

Lecture Notes, February 5, 2008 Gravity Effects of Simple Geometric Shapes • Sphere• Horizontal Cylinder• Vertical Cylinder• Inclined/Vertical Rod• Horizontal/Faulted Sheet Analyzing Anomalies • Regionals and Residuals Trend Surfaces Upward/Downward Continuation Second Derivatives

Lecture Notes, February 7, 2008 Analyzing Anomalies • Regionals and Residuals Filtering Gravity Interpretation • Half-Maximum Technique• Second Derivative Technique Applications of the Gravity Method

Lecture Notes, February 7, 2008 (continued) The Magnetic Method Magnetic Force Magnetic Field Strength Magnetic Moment Intensity of Magnetization

Lecture Notes, February 12, 2008 Magnetic Susceptibility Remanent Magnetization Earth’s Magnetic Field • Elements• Dipolar Nature www.ngdc.noaa.gov/seg/geomag/declination.shtml • Variations Measuring the Magnetic Field • Flux-Gate Magnetometer• Proton-Precession Magnetometer Field Procedures • Diurnal Corrections

Lecture Notes, February 14, 2008 Field Procedures • Elevation Corrections• Correcting for Horizontal Position Magnetic Effects of Simple Geometric Shapes • Rock Susceptibilities• Effect of an isolated pole• Effect of a dipole• Effect of a sphere

Lecture Notes, February 19, 2008 Guest Lecturer: Dr. Bill Roggenthen Deep Underground Science and Engineering Laboratory (DUSEL)

Lecture Notes, February 21, 2008 •Magnetic Effects of Simple Geometric Shapes (continued) •Thin horizontal sheet •Polygons with infinite strike length •Interpretation of Magnetic Data •Advantages/Disadvantages •Quantitative Interpretative Techniques •Half maximum techniques •Slope methods •Computer modeling

Lecture Notes, February 21, 2008 (continued) •Applications of the Magnetic Method •Archeological Surveys •Detecting Voids •Detecting Metal Objects •Mineral Exploration •Love (2008) paper on magnetics

Lecture Notes, February 26, 2008 •Examination I •Exploration with the gravity method •Exploration with the magnetic method

Lecture Notes, February 28, 2008 • Paleomagnetism • Electromagnetic Surveying • Electromagnetic Waves • Wavelengths • Frequencies • AC/DC • Electrical Resistivity • Electrical Conductivity • Dielectric Properties • Absorption and Attenuation

Lecture Notes, March 4, 2008 Guest Lecturer: Mark Anderson, USGS Using microgravity techniques to measure change in ground water storage

Lecture Notes, March 6, 2008 • Seismic Refraction Lab Review and Assignment • Electromagnetic Sounding • Frequency Domain EM Methods (FDEM) • SLINGRAM • Tilt-angle/Dip-angle methods • Very-Low Frequency (VLF) methods

Lecture Notes, March 11, 2008 • Electromagnetic Sounding (continued) • Time Domain EM Methods (TDEM) • EM Field Techniques • Sounding • Profiling • Interpretation • Ground-Penetrating Radar

Lecture Notes, March 13, 2008 Seminar: Jared Abraham, USGS Hydrogeologic Framework Studies for Determining Surface Water-Ground Water Relationships in the Glaciated Region of Eastern Nebraska Using Airborne and Ground Geophysics

Lecture Notes, March 25, 2008 • Ground-Penetrating Radar (continued) • Radar Velocity • Data Acquisition • Wide Angle Reflection and Refraction (WARR) • Common Midpoint (CMP) • Transillumination/Radar Tomography •GPR Velocity Analysis

Lecture Notes, March 25, 2008 (Continued) • Ground-Penetrating Radar (continued) • Walkaway Test • Diffraction Hyperbola • Applications of EM Surveying • Archeological Surveys • Geologic Applications • Snow and Ice Mapping • Environmental/Engineering Applications

Lecture Notes, March 27, 2008 • Seismic Waves and Wave Propagation • Wave Terminology • Elastic Coefficients • Young’s Modulus, Poisson’s Ratio, Bulk Modulus, Rigidity Modulus • Seismic Waves • Longitudinal Waves • Transverse Waves • Surface Waves

Lecture Notes, April 1, 2008 • Seismic Wave Velocities • Ray Paths in Layered Materials • Huygen’s Principle • Fermat’s Principle • Reflection • Refraction

Lecture Notes, April 3, 2008 • Snell’s Law • Critical Refraction • Diffraction • Wave Arrivals at the Surface

Lecture Notes, April 8, 2008 Guest lecturers on geophysical well logs and 3-D seismic data, S.D. Oil and Gas Program • Fred Steece• Mack McGillivray

Lecture Notes, April 10, 2008 Examination II • Electromagnetic Surveying EM waves and field techniques Ground penetrating radar • Seismic Exploration

Lecture Notes, April 15, 2008 Wave Attenuation and Amplitude • Spherical spreading• Absorption• Energy partitioning Energy Sources • Weight drops• Explosives• Vibratory techniques