Great Subduction Zone Earthquakes

During the past decade, one have witnessed a remarkable series of great subduction earthquakes, beginning with Sumatra, Japan, and Chile. Observational techniques have permitted Earth scientists to study these strong megathrust earthquakes in unprecedented detail and have revealed many unexpected results regarding the size of the seismogenic zone, along strike segmentation and lateral segment interaction over multiple seismic cycles. Heterogeneous seismogenic behavior of different subduction margins, likely due to variations in coupling, underscores the importance of detailed studies targeted to each zone, covering the longest possible observational period and including close monitoring of mature subduction zone segments. The state of stress of the downgoing plate outboard of the trench can potentially provide additional information on the degree of advancement of the seismic cycle and may help improve forecasts of imminent megathrust earthquakes.