The influence of off-fault deformation zones on the near-fault distribution of coseismic landslides

Abstract Coseismic landslides are observed in higher concentrations around surface-rupturing faults. This observation has been attributed to a combination of stronger ground motions and increased rock mass damage closer Past work shown it is difficult separate the influences from strong on landslide occurrence. We measured coseismic off-fault deformation (OFD) zone widths (treating them as proxy for areas more intense damage) using high-resolution, three-dimensional surface displacements 2016 Mw 7.8 Kaik?ura earthquake New Zealand. OFD zones vary width ~50 m 1500 over ~180 km length ruptures analyzed. Using densities database 29,557 landslides, we demonstrate that our captures density incidence than generic “distance fault rupture” within ~650 ruptures. result suggests effects (including trapped amplified seismic waves) may contribute near-fault occurrence addition influence regional motions, which attenuate with distance fault. The represents new path toward understanding, planning for, distribution Inclusion estimates improve susceptibility models decrease risk.