France), T. Camelbeeck (Royal Observatory, Brussels, Belgium), S. Stein, Department of Earth and Planetary Sciences, Northwestern University, USA, M. Liu (Department of Geological Sciences, University of Missouri, USA), T.J. Craig (Institute of Geophysics and Tectonics, University of Leeds, UK)
and Brodsky, Rep. Prog. Phys., 2004) Earthquakes result from the localized accrual of tectonic stress at long- lived active faults in a steady-sate system where a balance is achieved between the rates at which strain accrues and is released on faults. SCR faults = very, very, very, very slow faults.
in SCRs In the NMSZ, seismic strain release is ~one order of magnitude larger than strain accumulation over past 3,000 yrs Not steady-state Releases “fossil” strain GPS (upper bound) Strain accumulation rate
of migrating earthquakes in North China Liu et al., Lithosphere, 2011 Steady-state earthquake activity does not persist in the long-term on any single SCR fault. The Hebron fault, Namibia 50 km-long rupture Late Pleistocene to recent no current seismicity White et al., 2009
stress or fault strength that release elastic energy from a pre- stressed lithosphere rather that by the localized accrual of tectonic stress at long-lived active faults. in SCR settings, stress accrues at very slow rates and earthquakes occur as a result of fault strength change (black line, e.g., fluid pore pressure increase at seismogenic depth) or of transient stress perturbations (blue line, e.g., hydrological or sedimentary load change).
no previous seismicity and no surface evidence for strain accumulation. – They need not repeat, since the tectonic loading rate is close to zero. – Concepts of recurrence time or fault slip rate do not apply. • Some perspectives: – What data do other SCRs have to offer? Australia? – Is there evidence for a correlation between triggering mechanisms and earthquakes in SCRS? – How does SCR lithosphere stores strain? The Hebron fault, Namibia 50 km-long rupture, no current seismicity