Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5781205 | Journal of Geodynamics | 2017 | 37 Pages |
Abstract
The mechanism at the origin of the earthquakes below 30Â km remains elusive as these events cannot be explained by brittle frictional processes. In this work we focus on the global total distribution of earthquakes frequency vs. depth from â¼50Â km to 670Â km depth. We develop a numerical model of self-driven subduction by solving the non-homogeneous Stokes equation using the “Particle in cell method” in combination with a conservative finite difference scheme, here solved for the first time using Python and NumPy only. We show that most of the elastic energy is stored in the slab core and that it is strongly correlated with the earthquake frequency-depth distribution for a wide range of lithosphere and lithosphere-core viscosities. According to our results, we suggest that 1) slab bending at the bottom of the upper mantle causes the peak of the earthquake frequency-depth distribution that is observed at mantle transition depth; 2) the presence of a high viscous stiff core inside the lithosphere generates an elastic energy distribution that fits better with the exponential decay that is observed at intermediate depth.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Earth-Surface Processes
Authors
P.M. Gunawardana, G. Morra,