Finite element modelling of elastic intraplate stresses due to heterogeneities in crustal density and mechanical properties for the Jabalpur earthquake region, central India

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.

Crustal density structure across the Central Indian Shear Zone from gravity data

“…(b) Final gravity model derived by introducing small scale bodies of exposed geology and altering the geometry and density (in g/cm 3 ) of the initial gravity model. layer is further suggested 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 (Manglik et al, 2008). The Pn velocity, a major source of information on the petrologic nature of the upper mantle, is unfortunately not discernable along Seoni-Kalimati seismic profile.…”

Multi-GPU and multi-CPU accelerated FDTD scheme for vibroacoustic applications

“…In this case a dense grid is used, thus GPU computing has been considered in order to reduce the overall time simulation costs up to 5 min with the Peer-to-Peer CUDA version. The parameters of the different layers are summarised in Table 1 and have been extracted from [30,31]. Fig.…”

An engineering model for seismicity of India

“…The modelling is done assuming plane stress condition because the thickness of the plate is relatively small compared to the in-plane dimensions. The model has homogeneous solid section of 60 km thickness at the continental crust (Manglik et al 2008). The thickness of the cratons is fixed by trial and error.…”

“…Homogeneous mechanical properties are assumed throughout the Indian plate. Young's modulus and Poisson's ratio for rock are taken as 75 GPa and 0.25, respectively (Manglik et al 2008). The boundary condition along the continental collision Himalayan boundary can be hinged or fixed in the model with regard to the fact that the displacements near the boundary are very small compared to those far away from the boundary.…”