On the Relationships Between Geodynamics and Megathrust Seismicity

Abstract

Subduction megathrusts host the Earth's largest earthquakes, also known as giant earthquakes (i.e., Mw≥8.5). As demonstrated by the 2004 Sumatra-Andaman (Mw = 9.2), 2008 Maule (Mw = 8.8), and 2011 Tohoku-Oki (Mw = 9.1) earthquakes, these big events are a major threat to society. Thus, understanding the spatial and temporal occurrence of such disastrous events is pivotal for seismic hazard assessment of subduction zones. Over time, various studies have proposed possible cause-effect relationships between subduction zone parameters and megathrust seismogenic behavior. In this article, I address the geodynamic conditions that may favor the occurrence of giant megathrust earthquakes and summarize the current state of knowledge of this subject. Limitations and future perspectives related to the study of megathrust seismicity are discussed as well.