Empirical Analysis of Global-Scale Natural Data and Analogue Seismotectonic Modelling Data to Unravel the Seismic Behaviour of the Subduction Megathrust

Abstract

Subduction megathrusts host the Earth’s greatest earthquakes as the 1960 Valdivia (Mw9.5, Chile), the largest earthquake instrumentally recorded, and the recent 2004 Sumatra-Andaman (Mw9.2, Indonesia), 2010 Maule (Mw8.8, Chile), and 2011 Tohoku-Oki (Mw9.1,Japan) earthquakes triggering devastating tsunamis and representing a major hazard tosociety. Unravelling the spatio-temporal pattern of these events is thus a key for seismichazard assessment of subduction zones. This paper reviews the current state ofknowledge of two research areas–empirical analysis of global-scale natural data andexperimental data from an analogue seismotectonic modelling—devoted to study cause-effect relationships between subduction zone parameters and the megathrustseismogenic behavior. The combination of the two approaches overcomes theobservational bias and inherent sampling limitations of geological processes(i.e., shortness of instrumental and historical data, decreasing completeness andresolution with time into the past) and allows drawing appropriately from multipledisciplines with the aim of highlighting the geodynamic conditions that may favor theoccurrence of giant megathrust earthquakes.