Shallow megathrust earthquake ruptures betrayed by their outer-trench aftershocks signature

- Outer-rise aftershocks sequences are conditioned by shallow rupture of the megathrust.
- Along-trench distribution of outer-rise aftershocks is modulated by shallow slip.
- Outer-rise aftershock sequences are triggered by static-stress transfer.
- Outer-rise aftershocks can help constrain past and future shallow megathrust ruptures.