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  • Modeling of Continental Nor...
    Muldashev, Iskander A.; Pérez‐Gussinyé, Marta; Sobolev, Stephan V.

    Geochemistry, geophysics, geosystems : G3, December 2022, 2022-12-00, 20221201, 2022-12-01, Letnik: 23, Številka: 12
    Journal Article

    The magnitude of earthquakes on continental normal faults rarely exceeds 7.0 Mw. However, because of their vicinity to large population centers they can be highly destructive. Long recurrence time, relatively small deformations, and limited observations hinder our understanding of the deformation patterns and mechanisms controlling the magnitude of events. Here, this problem is addressed with 2D thermomechanical modeling of normal fault seismic cycles. The 2020 Samos, Greece Mw7.0 earthquake is used as an example as it is one of the largest and most studied continental normal fault earthquakes. The modeling approach employs visco‐elasto‐plastic rheology, compressibility, free surface, and a rate‐and‐state friction law for the fault. Modeling of the Samos earthquake suggests the pore fluid pressure ratio on the fault ranges from 0 to 0.7. The model demonstrates that most of the deformation during interseismic and coseismic periods, besides on the fault, occurs in the hanging wall and footwall below the seismogenic part of the fault. The largest vertical surface displacement during the earthquake is the subsidence of the hanging wall in the vicinity of the fault, while the uplift of the footwall and remote part of the hanging wall is significantly smaller. Modeling of the seismic cycles on normal faults with different setups shows the dependency of the magnitude on the thermal profile and dipping angle of the fault; low heat flow and low dipping angle are favorable conditions for the largest events, while steep normal faults in the areas of high heat flow tend to have the smallest magnitudes. Key Points We use numerical modeling to investigate continental normal fault earthquakes, using the 2020 Samos Mw7.0 earthquake as an example Most of the deformation during the seismic cycle, besides on the fault, occurs in the crust below the seismogenic part of the fault Low dipping angle and low heat flow favor larger magnitudes of normal fault earthquakes