Lithospheric flexural modelling of the seaward and trenchward of the subducting oceanic plates |
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| Authors: | Jiangyang Zhang Zhen Sun |
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| Institution: | 1. Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences , Guangzhou, China;2. University of Chinese Academy of Sciences , Beijing, China;3. Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences , Guangzhou, China |
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| Abstract: | ABSTRACT Based on a two-segment plate flexural modelling, we investigated the effective elastic thickness of global subducting oceanic lithosphere. Our results show that for the plate age of 0 to 50 Ma, the seaward effective elastic thickness T e M values are located between 600 and 900°C isotherms, and do not track any isotherm, while the majority of the trenchward effective elastic thickness T e m values are located between 300 and 600°C isotherms. For the plate age older than 50 Ma, T e M values basically matches the 600°C isotherm with some fluctuations for the age older than 110 Ma, while T e m values mainly fall between 200 and 400°C isotherms. The reduction in effective elastic thickness (T e M-T e m) varies from 2.6 to 30.1 km, or 11–68% of seaward T e M. Thus, the absolute value of the decrease in the effective elastic thicknesses (T e M-T e m) increases with the plate age, while the percentage reduction in the effective elastic thickness (1-T e m/T e M) has no obvious relationship with the age, but more related to the curvature of bending plate. Almost all bending-related earthquakes occurred above the T e M line, but many normal-faulting earthquakes are deeper than the T e M-T e m line, implying that the plate may still retain some thickness of an elastic property core in the areas (depth) where earthquakes occur. |
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| Keywords: | Plate flexure modelling trench oceanic crust age reduction in effective elastic thickness |
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