What happens when two slow slip events merge together ? Below is a movie of what we observed during such a merging episode which took place in 2013 along the Casacadia subduction fault :

We observed an increase in moment rate release of a factor 10 during the episode, suggesting that the merging of slow slip events is an efficient mechanism to promote instability and  therefore a possible mechanism for initiating earthquakes (Bletery and Nocquet, Nature Communications, 2020).

Two outreach articles (in french) on the study by CNRS info and IRD le Mag'.