Laboratory Investigation of Tilt and Seismicity Anomalies in Rock Before Failure.
Nature 1976 Mar; 260(5547):108-111
Tilt and seismicity anomalies whose time durations are a few milliseconds are shown to precede failure in dry rock specimens. The observed tilt and seismicity behaviour is qualitatively similar to that reported to precede earthquakes. Test results suggest that this precursor time for laboratory specimens of this length may be independent of rock type, in agreement with theoretical predictions and other experimental data on rock failures including earthquakes.
Nature, V. 260, No. 5547, Mar. 11, 1976, PP. 108-111