<< The model confirmed that the Kaikoura earthquake involved a complex cascade of fault ruptures, which propagated in a zig-zag fashion. Propagation velocities along the individual fault systems were not unusually slow, but the complex geometry of the fault network and delays at the transitions between fault segments led to a tortuous rupture path. >>
A surprising, cascading earthquake. Ludwig Maximilian University of Munich. Mar 20, 2019.
https://m.phys.org/news/2019-03-cascading-earthquake.html
<< the complex fault system operates at low apparent friction thanks to the combined effects of overpressurized fluids, low dynamic friction and stress concentrations induced by deep fault creep. >>
Thomas Ulrich, Alice-Agnes Gabriel, et al. Dynamic viability of the 2016 Mw 7.8 Kaikoura earthquake cascade on weak crustal faults. Nature Comm. volume 10, Article number: 1213 (2019) Mar 14