This paper is interesting. I just noticed it yesterday, although Paul (who was in my HS class) and 4th author Joan works just down the hall) has been working on it for a while.

So far as I know, it is just a surprising observation, not a model. They shake some glass beads sliding against each other and notice the pattern of slip events changes. They have ideas which details might be important - shaking-induced compaction of fault gouge material, but the numbers don't work very well yet.

In general, triggering is thought perhaps to be proportional to the stress in the triggering waves, although alternatively, it might be proportionate to the kinetic energy, as is the situation for triggering landslides, but these are details.