Forecasting of Rock Failure in the Laboratory using Active Acoustic
Monitoring Methods
Abstract
Predicting stress changes in the subsurface leading to failure or
seismicity remains challenging. Developing a robust monitoring method
can help the prediction and thus mitigation of natural hazards.
Ultrasonic transmission experiments were performed on Red Pfaelzer
sandstones to investigate the forecasting potential to failure at
different confining pressures. The forecasting potential for failure of
the energy of the direct and coda wave, the transmissivity, Q-factor,
coda wave decorrelation coefficient, and velocity change by coda wave
interferometry are investigated and compared. Our results show the
failure of the tested samples can be forecasted from 40 to 70% of the
failure point. Small differences are visible in the precursors between
the tested confining pressures, but as the trends are very similar, a
robust prediction of failure can be made by combining the various
analyses techniques. In this paper, we propose a traffic light
forecasting system using active acoustic monitoring which is applicable
for forecasting failure at various depths and or stress conditions, for
a better prediction of small stress-induced changes in the subsurface
and thus mitigation of failure (and seismicity) in the subsurface.