Megathrust earthquakes are the most powerful type of earthquake, occurring at subduction zones -- where one tectonic plate is pushed beneath another. By contrast, slow slip events (SSEs) release seismic stress at a lower rate than large earthquakes, re-occurring in cycles. These processes can take place along the megathrust and other planes of weakness in response to loading, releasing low frequency seismic waves. Researchers in Japan consider the fluid drainage processes that can occur from SSEs and their impact on seismic activity.