Dynamic stress triggering in the 2010-2011 Canterbury earthquake sequence

Caroline Holden, Charles A. Williams, & David A. Rhoades

Published August 10, 2016, SCEC Contribution #6623, 2016 SCEC Annual Meeting Poster #195

The Canterbury earthquake sequence started in 2010 with the M7.1 Darfield earthquake. It was followed by over 10,000 aftershocks including the tragic M6.2 February 2011 Christchurch earthquake and the latest M5.7 Valentine earthquake (Kaiser et al., 2016). Steacy et al. (2013) suggest that 100% of the M5.5+ aftershocks occur in regions of increased static Coulomb stress changes. In this study we investigate the role of dynamic stress triggering on aftershock production, with a particular emphasis on the static and dynamic effects on smaller aftershocks.
Based on the kinematic source models of Holden (2011, 2012), we calculate dynamic stressgrams: expressions of the evolution in time of the stress tensor at specific locations. We then derive time-dependent Coulomb failure stress values and respective peak dynamic stress values, as well as other stress-related quantities. For comparison, we also compute static stress values using both the same source models as the dynamic calculations, as well as more complex source models based on geodetic inversions. We produce interpolated maps of these metrics.
Finally we statistically compare the correlation of aftershock production with the static and dynamic approaches. We do so for a range of triggering times and a range of magnitudes

Key Words
Coulomb stress, Canterbury sequence, aftershocks

Holden, C., Williams, C. A., & Rhoades, D. A. (2016, 08). Dynamic stress triggering in the 2010-2011 Canterbury earthquake sequence. Poster Presentation at 2016 SCEC Annual Meeting.

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