2013/10/22 by Paul A. Johnson, P. A. Johnson, B. Ferdowsi +15 · 151 citations
Earth and Planetary Sciences · Engineering · #Acoustic emission #Composite material #Geotechnical and Geomechanical Engineering #High-pressure geophysics and materials #Materials science #Physics #Shear (geology) #Shearing (physics) #Slip (aerodynamics) #Thermodynamics #earthquake and tectonic studies
paper · open access · doi:10.1002/2013gl057848
published in Geophysical Research Letters 40(21), 5627-5631 (American Geophysical Union)
openalex publication_date 2013/10/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
Abstract We investigate the physics of laboratory earthquake precursors in a biaxial shear configuration. We conduct laboratory experiments at room temperature and humidity in which we shear layers of glass beads under applied normal loads of 2–8 MPa and with shearing rates of 5–10 µm/s. We show that above ~ 3 MPa load, acoustic emission (AE), and shear microfailure (microslip) precursors exhibit an exponential increase in rate of occurrence, culminating in stick‐slip failure. Precursors take place where the material is in a critical state—still modestly dilating, yet while the macroscopic frictional strength is no longer increasing.