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Genesis of mega-thrust earthquakes events at convergent plate boundaries: 3D modelling of seismic coupling combining geodynamic and earthquake-faulting models

English title Genesis of mega-thrust earthquakes events at convergent plate boundaries: 3D modelling of seismic coupling combining geodynamic and earthquake-faulting models
Applicant Mai Paul Martin
Number 125274
Funding scheme Project funding
Research institution Institut für Geophysik ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Geophysics
Start/End 01.06.2009 - 31.05.2012
Approved amount 168'775.00
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Keywords (10)

kinematics and geodynamics of subduction zones; mega-thrust earthquakes; numerical modeling of geodynamical processes; analogue studies of subduction environments; earthquake source physics; dynamic rupture modeling; simulation-based seismic hazard; large tsunami-generating earthquakes; geodynamics at convergent plate boundaries;

Lay Summary (English)

Lead
Lay summary
Subduction zones are the location of the largest and most hazardous earthquakes on Earth. They are characterized by the convergence of two lithospheric plates, one sliding underneath the other. The contact surfaces of converging plates constitute major fault zones at which a large fraction of the global seismicity occurs. However, in spite of the superficial similarity of convergent margins, the statistical distributions of large earthquakes on different subduction zones are different: some regions are characterized by large mega-thrust earthquakes while others show only minor seismic activity, dominated by moderate-size earthquakes. Lithospheric forces at convergent boundaries induce the release of both thrust and strike-slip earthquakes, occurring on a different set of faults that exist at the plate interface and within the overriding plate. The goal of this project is to develop a fully coupled geodynamical-seismological model of subduction zone seismicity, considering the wide range of interacting space-time scales that are necessary to capture the prominent physics of this system.Geodynamics and the physics of earthquake faulting are relatively young disciplines. Geodynamical processes have been understood within a hierarchical framework, i.e. the larger scale induces smaller scale processes. This top-down structure however breaks down at the scale of seismic faults, where the nonlinear physics of the dynamic earthquake rupture process is characterized by the interaction between different scales (i.e. even a localized small perturbation may lead to earthquake nucleation which eventually triggers a large event). In this project, we propose to model the entire system by coupling two different modeling approaches, each adapted to its physics, considering also innovative laboratory modeling techniques, to investigate specific geometries and parameter-space ranges and their effects on the occurrence. The modeling of subduction processes helps to characterize the behavior of a single subducting plate (with pre-existing faults). Likewise, simulations of long-term slip histories and source processes under nonlinear friction for assumed strike-slip faults allow for examining seismicity statistics and earthquake complexity. The next step to improve our understanding of subduction-related physics and the genesis of mega-thrust earthquakes combines various numerical and laboratory tools that allow us to define the relationship between geodynamics, seismic coupling and thrust-faulting dynamics. This project is targeted towards this ambitious goal.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Exhumation and subduction erosion in orogenic crustal wedges: insights from numerical models
van Dinther Ylona (2012), Exhumation and subduction erosion in orogenic crustal wedges: insights from numerical models, in Geochemisty, Geophysics, Geosystems, 13(6), 1-18.
The long- term seismic cycle at a subduction thrust: comparing geodynamic numerical simulations to analogue models
van Dinther Ylona (2011), The long- term seismic cycle at a subduction thrust: comparing geodynamic numerical simulations to analogue models, in International Union of Geodesy and Geophysics, General Assembly, Melbourne, Australia, 02-07-2011International Union of Geodesy and Geophysics, General Assembly, Melbourne, Australia, 02-07-2011.
Role of the overriding plate in the subduction process: Insights from numerical models
van Dinther Ylona (2010), Role of the overriding plate in the subduction process: Insights from numerical models, in Tectonophysics, (484), 74-86.
The seismic cycle at subduction thrusts: 1. insights from laboratory models,
Corbi Fabio, The seismic cycle at subduction thrusts: 1. insights from laboratory models,, in J. Geophys. Res..
The seismic cycle at subduction thrusts: 2. Dynamic implications of geodynamic simulations benchmarked with laboratory models
van Dinther Ylona, The seismic cycle at subduction thrusts: 2. Dynamic implications of geodynamic simulations benchmarked with laboratory models, in J. Geophys. Res..

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Invited geophysical seminar at Utrecht University 27.06.2012 Utrecht
Swiss Geoscience Meeting, Zurich, Switzerland, 12.11.2011 Zurich
International Union of Geodesy and Geophysics - General Assembly, Melbourne, Australia 02.07.2011 Melbourne


Associated projects

Number Title Start Funding scheme
169880 Spatio-temporal variability of subduction zone seismicity from 2D and 3D seismo-thermo-mechanical models 01.04.2017 Project funding
144398 Genesis of mega-thrust earthquakes at convergent plate boundaries: modelling of seismic coupling combining geodynamic and earthquake-faulting models 01.10.2012 Project funding
153524 Spatio-temporal variability of subduction zone seismicity from seismo-thermo-mechanical models 01.04.2014 Project funding

Abstract

Subduction zones are the location of the largest and most hazardous earthquakes on Earth. They are characterized by the convergence of two lithospheric plates, one sliding underneath the other. The contact surfaces of converging plates constitute major fault zones at which a large fraction of the global seismicity occurs. However, in spite of the superficial similarity of convergent margins, the statistical distributions of large earthquakes on different subduction zones are different: some regions are characterized by large mega-thrust earthquakes while others show only minor seismic activity, dominated by moderate-size earthquakes.Lithospheric forces at convergent boundaries induce the release of both thrust and strike-slip earthquakes, occurring on a different set of faults that exist at the plate interface and within the overriding plate. The physical relationship between seismicity and tectonic stresses is known as “seismic coupling” (first introduced by Kanamori, 1971) to characterize the role of intra-plate effects at convergent margins. Several studies attempt to further quantify the seismic coupling (Peterson and Seno, 1984, Scholz and Campos, 1995, Hyndman et al, 1997, Scholz and Small, 1997, McCaffrey, 1997, Kavasaki et al, 2001, Conrad et al., 2004), but a fully coupled geodynamical-seismological model of subduction zone has never been derived, due to the wide range of interacting space-time scales which are cumbersome to explore. Another difficulty is the poorly understood origin of seismic coupling, being a combination of both endogenic and exogenic effects that govern the faulting behavior. Geodynamics and the physics of earthquake faulting are relatively young disciplines. Geodynamical processes have been understood within a hierarchical framework, i.e. the larger scale induces smaller scale processes. This top-down structure however breaks down at the scale of seismic faults, where the intrinsically nonlinear physics of the dynamic rupture process of earthquakes faulting is characterized by the interaction between different scales (i.e. even a localized small perturbation may lead to earthquake nucleation which eventually triggers a large event). In general, these two systems are modeled employing distinct sets of equations (quasi-static in geodynamics, quasi-dynamic and dynamic for earthquake ruptures) and different numerical approaches. In this project, however, we propose to model the entire system by coupling two different modeling approaches, each adapted to its physics, considering also innovative laboratory modeling techniques, to investigate specific geometries and parameter-space ranges and their effects on the occurrence and properties of mega-thrust earthquakes at subduction interfaces.The modeling of subduction processes helps to characterize the behavior of a single subducting plate (with pre-existing faults). Likewise, simulations of long-term slip histories and source processes under nonlinear friction for assumed strike-slip faults allow for examining seismicity statistics and earthquake complexity. The next logical step to improve our understanding of subduction-related physics, to gain insight into the genesis of mega-thrust earthquakes and the seismic hazard in proximity of subduction zones is clear: we now have to combine the various numerical and laboratory tools that allow us to define the relationship between geodynamics, seismic coupling and thrust-faulting dynamics. This project is targeted towards this ambitious goal.
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