Finite element modelling of elastic intraplate stresses due to heterogeneities in crustal density and mechanical properties for the Jabalpur earthquake region,central India |
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| Authors: | A Manglik S Thiagarajan A V Mikhailova Yu Rebetsky |
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| Institution: | (1) National Geophysical Research Institute, Uppal Road, Hyderabad, 500 007, India;(2) Schmidt Institute of Physics of Earth, 10 B. Gruzinskaya Street, 123995 Moscow, Russia |
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| Abstract: | Deep lower crustal intraplate earthquakes are infrequent and the mechanism of their occurrence is not well understood. The
Narmada-Son-lineament region in central India has experienced two such events, the 1938 Satpura earthquake and the 1997 Jabalpur
earthquake, having a focal depth of more than 35 km. We have estimated elastic stresses due to the crustal density and mechanical
properties heterogeneities along the Hirapur-Mandla profile passing through the Jabalpur earthquake region to analyse conditions
suitable for the concentration of shear stresses in the hypocentral region of this earthquake. Elastic stresses have been
computed by a finite element method for a range of material parameters. The results indicate that the shear stresses generated
by the density heterogeneities alone are not able to locally enhance the stress concentration in the hypocentral region. The
role of mechanical properties of various crustal layers is important in achieving this localization of stresses. Among a range
of material parameters analysed, the model with a mechanically strong lower crust overlying a relatively weak sub-Moho layer
is able to enhance the stress concentration in the hypocentral region, implying a weaker mantle in comparison to the lower
crust for this region of central India. |
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| Keywords: | Elastic stresses continental crust intraplate seismicity rheology geodynamics modelling seismology |
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