Seismic fatigue failure may have triggered the 2014 Mw7.9 Rat Islands earthquake

Abstract

Seismic waves propagating from large earthquakes cause global transient stress changes capable of triggering other earthquakes at great distances. The study of such remote and dynamic triggering phenomena provides a better understanding of the mechanisms that generate earthquakes. I introduce an integrated seismicity model to stochastically evaluate the time intervals of consecutive earthquakes at global scales, making it possible to detect a pair of earthquakes possibly related to each other. I show a Mw7.9 intermediate-depth earthquake that occurred in the Rat Islands in 2014 is inferred to have been associated with a sequence of distant large (Mw≥6.5) earthquakes originating from the Kermadec Islands. The passage of seismic surface waves from the Kermadec events that produced small stress changes varying within at most 10 Pa at the hypocenter, probably caused a reduction in the fault's strength by cyclic fatigue and eventually triggered its failure during their passage.