A NEW PARADIGM FOR LARGE EARTHQUAKES IN STABLE CONTINENTAL PLATE INTERIORS

Eric Calais, Thierry Camelbeeck, Seth Stein, Mian Liu, Timothy Craig
2017 unpublished
Large earthquakes within stable continen-3 tal regions (SCR) show that significant amounts 4 of elastic strain can be released on geological 5 structures far from plate boundary faults, where 6 the vast majority of the Earth's seismic ac-7 tivity takes place. SCR earthquakes show spa-8 tial and temporal patterns that differ from those 9 at plate boundaries and occur in regions where 10 tectonic loading rates are negligible. However, 11 in the absence of a more appropriate model, 12 they are
more » ... el, 12 they are traditionally viewed as analogous to 13 their plate boundary counterparts, occuring 14 when the accrual of tectonic stress localized 15 at long-lived active faults reaches failure thresh-16 old. Here we argue that SCR earthquakes are 17 better explained by transient perturbations 18 of local stress or fault strength that release elas-19 tic energy from a pre-stressed lithosphere. As 20 a result, SCR earthquakes can occur in regions 21 with no previous seismicity and no surface ev-22 idence for strain accumulation. They need not 23 repeat, since the tectonic loading rate is close 24 D R A F T September 10, 2016, 4:34pm D R A F T CALAIS ET AL.: LARGE EARTHQUAKES IN SCRS X -3 to zero. Therefore, concepts of recurrence time 25 or fault slip rate do not apply. As a consequence, 26 seismic hazard in SCRs is likely more spatially 27 distributed than indicated by paleoearthquakes, 28 current seismicity, or geodetic strain rates.
doi:10.1130/abs/2017am-303722 fatcat:vom2vbaxifgc3j6lwwjvsnqxsu