Master of Science in Electrical Engineering (MSEE)
Electrical and Computer Engineering
Commercial geophones have been used in the field of geology for many years. They are commonly used to detect oil and gas deposits and create three dimensional simulations of the earth. Geophones are commonly made up of a spring mounted magnetic mass moving back and forth in a wire coil to create a voltage. The response of the coil is proportional to the velocity of the ground. At various frequencies, seismic events can be measured using a geophone. However, most commercial geophones only allow accurate measurements of frequencies down to approximately five hertz. By using a feedback circuit, an attempt will be made to accurately measure seismic motions at lower sensor frequencies. This will be evaluated with a shaking table that is displaced at known frequencies, taking measurements of the output of the feedback circuit. The results of the feedback circuit will be compared to the results taken of the geophone on the same shaking table to show how much better this device will detect seismic activities at lower frequencies.
Document Availability at the Time of Submission
Release the entire work immediately for access worldwide.
Holden, Brian Michael, "Low Frequency Improvements to Commercial Geophones" (2014). LSU Master's Theses. 3275.