Coulomb Stress Change Sensitivity due to Variability in Mainshock Source Models and Receiving Fault Parameters: A Case Study of the 2010-201. Christchurch, New Zealand, Earthquakes

Fault Location and Slip Distribution of the 22 February 2011 Mw 6.2 Christchurch, New Zealand, Earthquake from Geodetic Data

“…This indicates that stress changes due to Darfield almost immediately caused significant earthquake activity in the vicinity of the future February earthquake. Calculations by ourselves and others (e.g., Zhan et al 2011, page 800 of this issue) show positive but very small Coulomb stress changes from Darfield in the region of the February quake; these results do not highlight eastern Christchurch as a region of large Coulomb stress increase. The Christchurch event seems less complex than Darfield, with most of the surface deformation (away from the liquefaction regions) explicable by slip on two sub-parallel fault planes; the Darfield event involved several reverse fault segments in addition to the main strike-slip fault.…”

Hydrological effects of theMW7.1 Darfield (Canterbury) earthquake, 4 September 2010, New Zealand

“…Some earthquakes generate patterns of groundwater level change that mimic the pattern of volumetric strain, such as an X-shaped pattern of rise and fall in compressional and dilational quadrants around a strike-slip fault (e.g., Jonsson et al 2003). However an X-shaped pattern of rises and falls predicted by strike-slip Coulomb stress change models (e.g., CA Williams et al 2011;Zhan et al 2011) did not develop in groundwater levels around the right-lateral Greendale Fault. Instead, the symmetric O-shaped pattern centred on the fault (Fig.…”

Considering large earthquake clustering in seismic risk analysis

“…King (2007) showed that small errors in dip and strike, such as simplified fault geometry, do not significantly impact the stress values except in the near field. Zhan et al (2011) observed that different slip models only result in significant differences in the near field. Near-field analysis is important for the study of the distribution of small aftershocks but not so for the study of fault segment coupling.…”

“…This coupling can be the association of a great mainshock and its largest aftershock where both events occur on distinct fault segments, such as the 2010 M w 7.1 Canterbury, New Zealand, mainshock and its 2011 M w 6.3 Christchurch aftershock (Zhan et al 2011). There is also the case of successive large earthquakes occurring on neighboring fault segments and within days or tens of days of each other.…”

“…The present work takes advantage of the GenMR framework's capability to cope with heterogeneous risk processes and describes its conceptual application. We consider as underlying physical processes (1) the Coulomb stress transfer theory (e.g., King et al 1994;King 2007;Nalbant et al 2005;Parsons et al 2000;Mueller et al 2004;Zhan et al 2011;Toda et al 1998;Parsons 2005) and (2) repeated building ductility capacity reduction (e.g., Iervolino et al 2014) based on simple relationships between interstory drift and spectral acceleration (e.g., Baker and Cornell 2006). While Coulomb stress transfer is well established, other processes could be considered such as fluid migration (e.g., Miller et al 2004).…”