Why do seismologists say that the main seismic event on August 6, 2007, near the Crandall Canyon mine was not a naturally occurring earthquake?
An early clue was that seismic recordings made by vertically-oriented sensors throughout the University of Utah’s network all began with a downward (dilatational) motion. Recordings of naturally occurring earthquakes resulting from slip on a fault should include a mix of both upward (compressional) and downward first motions in a predictable pattern. Click here for a more detailed explanation. Observing all downward first motions is consistent with a type of deformation in a mine in which the roof and floor of part of the mine suddenly move toward each other as the space between them closes, either partially or totally. Depending on the distribution of recording stations, first-motion information alone may not conclusively determine what kind of source produced the observations. A good diagnostic tool for determining the source mechanism of seismic events involves the analysis of long-period seismic waves recorded on high-quality digital seismographs. A team of seismologists at the Uni
Related Questions
- Why do seismologists say that the main seismic event on August 6, 2007, near the Crandall Canyon mine was not a naturally occurring earthquake?
- How accurate is the location reported by seismologists for the main seismic event on August 6?
- Did seismic activity occur near the Crandall Canyon mine before the August 6 shock?
