| Locating a seismic source with an unknown origin time using one three-component (3C) geophone is examined in this study. A series of twelve shots (sledgehammer impacts) were made in a degree-marked, semi-circular pattern at distances of 10 and 20 m from a single three-component geophone. Arrival times and wave form data from these shots were placed into random filenames to ensure a "blind" test, and then examined to try and determine the source direction and distance from the recording sensor. Distances were calculated utilizing the difference in arrival time between the critically refracted P wave and the Rayleigh wave, and shot azimuths were found through the use of 1st quarter cycle hodographs (horizontal particle motion graphs). P- and Rayleigh-wave velocities were obtained using conventional refraction surveys and other calibration shots. Eleven of the twelve "distance-surveys" predicted source distances with 10% or less error, and eight of the ten "radial-surveys" predicted shot azimuths (sometimes called "backazimuths") within 7° or less error. The ability to acquire data through this method, potentially in real-time, creates many new possibilities for the use of three-component data acquisition and analysis in military applications, energy resource exploration, and engineering. |
