Lecture, three hours; laboratory, three hours. Requisites: course M71; Mathematics 3A, 3B, and 3C, or 31A, 31B, and 32A; Physics 1A, 1B, 4AL, and 4BL, or 5A and 5B. Recommended: course M171. Methods and knowledge involved in investigation of near-surface geophysics. Covers gravity fields, wave equations, seismic ray theory, reflection and refraction, seismic interpretation, basic earthquake source theory, and introduction to magnetic fields and electrical resistivity. P/NP or letter grading.