sentences:  There is narrow band of deep earthquakes beneath southern IBM between ~21°N and ~17°N, but south of this there are extremely few deep events.Although early studies assumed that seismicity demarcated the upper boundary of the slab, more recent evidence has shown that many of these earthquakes occur within the slab.For instance, a study by showed that a region of events beneath northernmost IBM region occur ~20 km beneath the top of the subducting plate.