TY  - JOUR
A1  - Muldashev, Iskander A.
A1  - Sobolev, Stephan
T1  - What controls maximum magnitudes of giant subduction earthquakes?
JF  - Geochemistry, geophysics, geosystems
N2  - Giant earthquakes with magnitudes above 8.5 occur only in subduction zones. Despite the developments made in observing large subduction zone earthquakes with geophysical instruments, the factors controlling the maximum size of these earthquakes are still poorly understood. Previous studies have suggested the importance of slab shape, roughness of the plate interface contact, state of the strain in the upper plate, thickness of sediments filling the trenches, and subduction rate. Here, we present 2-D cross-scale numerical models of seismic cycles for subduction zones with various geometries, subduction channel friction configurations, and subduction rates. We found that low-angle subduction and thick sediments in the subduction channel are the necessary conditions for generating giant earthquakes, while the subduction rate has a negligible effect. We suggest that these key parameters determine the maximum magnitude of a subduction earthquake by controlling the seismogenic zone width and smoothness of the subduction interface. This interpretation supports previous studies that are based upon observations and scaling laws. Our modeling results also suggest that low static friction in the sediment-filled subduction channel results in neutral or moderate compressive deformation in the overriding plate for low-angle subduction zones hosting giant earthquakes. These modeling results agree well with observations for the largest earthquakes. Based on our models we predict maximum magnitudes of subduction earthquakes worldwide, demonstrating the fit to magnitudes of all giant earthquakes of the 20th and 21st centuries and good agreement with the predictions based on statistical analyses of observations.
KW  - giant earthquakes
KW  - earthquake modeling
KW  - subduction
Y1  - 2020
U6  - https://doi.org/10.1029/2020GC009145
SN  - 1525-2027
VL  - 21
IS  - 9
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Sobolev, Stephan Vladimir
A1  - Muldashev, Iskander A.
T1  - Modeling Seismic Cycles of Great Megathrust Earthquakes Across the Scales With Focus at Postseismic Phase
JF  - Geochemistry, geophysics, geosystems
Y1  - 2017
U6  - https://doi.org/10.1002/2017GC007230
SN  - 1525-2027
VL  - 18
SP  - 4387
EP  - 4408
PB  - American Geophysical Union
CY  - Washington
ER  -