Design and Application of an Electromagnetic Vibrator Seismic Source

Abstract

Vibrational seismic sources frequently provide a higher-frequency seismic wavelet (and therefore better resolution) than other sources, and can provide a superior signal-to-noise ratio in many settings. However, they are often prohibitively expensive for lower-budget shallow surveys. In order to address this problem, I designed and built a simple but effective vibrator source for about one thousand dollars. The ‘‘EMvibe’’ is an inexpensive electromagnetic vibrator that can be built with easy-to-machine parts and off-the-shelf electronics. It can repeatably produce pulse and frequency-sweep signals in the range of [Formula: see text], and provides sufficient energy for recording at offsets up to [Formula: see text]. Analysis of frequency spectra show that the EMvibe provides a broader frequency range than the sledgehammer at offsets up to [Formula: see text] in data collected at a site with soft sediments in the upper several meters. The EMvibe offers a high-resolution alternative to the sledgehammer for shallow surveys. It is well-suited to teaching applications, and to surveys requiring a precisely-repeatable source signature.