Mechanism of Deep-focus Earthquakes Anomalous Statistics

TL;DR

This study reveals a periodic discrete structure in deep-focus earthquake distribution related to subduction zones, modeled as a complex system with a rigid coating on a soft substratum, providing insights into stress and material properties.

Contribution

It introduces a novel model of deep-focus earthquake patterns using complex systems theory, highlighting the role of lithosphere and upper mantle interactions.

Findings

Identified a 50 km periodic structure in earthquake distribution.

Estimated stress and Young's modulus in the upper mantle and lithosphere.

Linked earthquake patterns to the complex system model of rigid coating on soft substratum.

Abstract

Analyzing the NEIC-data we have shown that the spatial deep-focus earthquake distribution in the Earth interior over the 1993-2006 is characterized by the clearly defined periodical fine discrete structure with period L=50 km, which is solely generated by earthquakes with magnitude M 3.9 to 5.3 and only on the convergent boundary of plates. To describe the formation of this structure we used the model of complex systems by A. Volynskii and S. Bazhenov. The key property of this model consists in the presence of a rigid coating on a soft substratum. It is shown that in subduction processes the role of a rigid coating plays the slab substance (lithosphere) and the upper mantle acts as a soft substratum. Within the framework of this model we have obtained the estimation of average values of stress in the upper mantle and Young's modulus for the oceanic slab (lithosphere) and upper mantle.