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In this study, we analyze high-resolution tremor catalogs from northern Cascadia, Guerrero, and northern Kii Peninsula. We find that tremor often occurs in short bursts that repeatedly occupy the same source area within a slow slip event. We hypothesize that these bursts are driven by loading from slow slip in areas surrounding the tremor zone. Adopting a rate-and-state friction law with a velocity-weakening to velocity-strengthening transition, we develop a finite fault model in which the size of the slow slip zone is larger than that of the tremor zone. Tidal forcing is added. Many asperities are randomly distributed within the tremor zone in order to generate burst-like slip evolution while maintaining reasonable propagation speeds of the main slow slip front. We successfully reproduce the increasing recurrence intervals of the bursts as the main front moves across the tremor zone, as well as tidally modulated secondary fronts well behind the main front.

Plain Language Summary Episodic slow slip events, often accompanied by tectonic tremor, represent a significant component of the complete seismic cycle. However, their physical mechanisms remain elusive. In this study, we find that tremor in multiple subduction zones tends to occur in the form of short bursts. During a slow slip event, the tremor bursts, viewed as a proxy for the contemporaneous slow slip, occur repeatedly over the same source areas with recurrence intervals increasing until coinciding approximately with the tidal period. We successfully simulate this behavior with a laboratory-derived friction law. Our numerical model highlights the important role of fault heterogeneities and tides in controlling the short-term evolution of slow slip.