Invited review paper: Seismicity along the South American subduction zone: Review of large earthquakes, tsunamis, and subduction zone complexity

Earthquakes along the shallow South American subduction zone exhibit heterogeneous rupture characteristics, going back several centuries of the earthquake record in this area. This heterogeneity is manifest in several ways, such as changes in rupture mode from magnitude > 8 events during one century followed by smaller ones in other time periods, as well as unusual tsunami events. There is also an apparent interaction between earthquake rupture and subducting plate complexity in this region. Significant complexity exists on the subducting Nazca plate, including fracture zones and ridges such as the large Nazca Ridge. Several large magnitude earthquakes have occurred in the region of ridge subduction, but no earthquake rupture has ruptured through these features into adjacent regions, suggesting that these subducting features act to segment the margin. Other features, such as fracture zones and variable sediment thickness on the Nazca Plate, appear to influence earthquake behavior over a wide range of magnitude scales. Upper plate features such as crustal faults also lead to heterogeneous earthquake behavior. Here I provide an overview of seismicity along the margin since 1850 in the context of the subduction zone structures. This includes great earthquakes such as the 1906 Ecuador and 1960 Chile events. I also present results showing increased rupture complexity in moderate magnitude earthquakes that can also be linked to certain Nazca Plate features.