Observed along the roots of seismogenic faults where the locked interface transitions to a stably sliding one,
low-frequency earthquakes (LFEs) primarily occur as event bursts during slow slip. Using an event catalog from
Guerrero, Mexico, we employ a statistical analysis to consider the sequence of LFEs at a single asperity as a
point process, and deduce the level of time clustering from the shape of its autocorrelation function. We show
that while the plate interface remains locked, LFEs behave as a simple Poisson process, whereas they become
strongly clustered in time during even the smallest slow slip, consistent with interaction between different LFE
sources. Our results demonstrate that bursts of LFEs can result from the collective behavior of asperities whose
interaction depends on the state of the fault interface.