TY - JOUR
T1 - Coulomb pre-stress and fault bends are ignored yet vital factors for earthquake triggering and hazard
AU - Mildon, Z. K.
AU - Roberts, G. P.
AU - Faure Walker, J. P.
AU - Toda, S.
N1 - Funding Information:
This study was funded by the UK Natural Environmental Research Council (NERC) Studentship NE/L501700/1, NERC Urgency Grant NE/P01660X/1 (EEFIT Reconnaissance Mission to the Amatrice, Italy, 24/09/2016 Earthquake), and NERC Standard Grant NE/I024127/1. The method to model strike-variable faults was developed during a Japan Society for the Promotion of Science (JSPS) Short Term Fellowship PE15776 undertaken by the lead author with ST. Work was aided by a GBSF (Great Britain Saskawa Foundation) grant 4602 to JFW. Figures were generated using Generic Mapping Tools using 10m DEM available. We thank those who assisted with fieldwork (listed in alphabetical order), Andrew Watson, David Arnold, Francesco Iezzi, Laura Gregory, Luke Wedmore, Ken McCaffrey, and Peter Mildon, even if their opinions differ from our own.
Publisher Copyright:
© 2019, The Author(s).
PY - 2019/12/1
Y1 - 2019/12/1
N2 - Successive locations of individual large earthquakes (Mw > 5.5) over years to centuries can be difficult to explain with simple Coulomb stress transfer (CST) because it is common for seismicity to circumvent nearest-neighbour along-strike faults where coseismic CST is greatest. We demonstrate that Coulomb pre-stress (the cumulative CST from multiple earthquakes and interseismic loading on non-planar faults) may explain this, evidenced by study of a 667-year historical record of earthquakes in central Italy. Heterogeneity in Coulomb pre-stresses across the fault system is >±50 bars, whereas coseismic CST is <±2 bars, so the latter will rarely overwhelm the former, explaining why historical earthquakes rarely rupture nearest neighbor faults. However, earthquakes do tend to occur where the cumulative coseismic and interseismic CST is positive, although there are notable examples where earthquake propagate across negatively stressed portions of faults. Hence Coulomb pre-stress calculated for non-planar faults is an ignored yet vital factor for earthquake triggering.
AB - Successive locations of individual large earthquakes (Mw > 5.5) over years to centuries can be difficult to explain with simple Coulomb stress transfer (CST) because it is common for seismicity to circumvent nearest-neighbour along-strike faults where coseismic CST is greatest. We demonstrate that Coulomb pre-stress (the cumulative CST from multiple earthquakes and interseismic loading on non-planar faults) may explain this, evidenced by study of a 667-year historical record of earthquakes in central Italy. Heterogeneity in Coulomb pre-stresses across the fault system is >±50 bars, whereas coseismic CST is <±2 bars, so the latter will rarely overwhelm the former, explaining why historical earthquakes rarely rupture nearest neighbor faults. However, earthquakes do tend to occur where the cumulative coseismic and interseismic CST is positive, although there are notable examples where earthquake propagate across negatively stressed portions of faults. Hence Coulomb pre-stress calculated for non-planar faults is an ignored yet vital factor for earthquake triggering.
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U2 - 10.1038/s41467-019-10520-6
DO - 10.1038/s41467-019-10520-6
M3 - Article
C2 - 31227694
AN - SCOPUS:85067599342
SN - 2041-1723
VL - 10
JO - Nature Communications
JF - Nature Communications
IS - 1
M1 - 2744
ER -