Months-Long Subduction Slow Slip Events Avoid the Stress Shadows of Seismic Asperities

Abstract

With precise geodetic measurements, slow transient fault slip events with durations from days to years have been documented at subduction zones for two decades. Long-lasting transient events with durations longer than 100 days occur at the downdip edge of seismogenic zones. With such long durations, only a few events have been documented so far. Takagi et al. (2019, https://doi.org/10.1029/2018JB016738) propose a new methodology to detect these events and successfully apply it to the Nankai subduction zone in which they characterize 24 events, including 11 new detections. Combined with other observations from around the Pacific rim, they suggest that the lateral segmentation of long-lasting slow slip events is controlled by the location of seismic asperities associated with their stress shadows.