Seismic waves and earthquakes in a global monolithic model

TL;DR

This paper presents a unified 'monolithic' model that couples seismic wave propagation, tectonic activity, and Earth's layered structure, incorporating complex physical effects and providing rigorous mathematical analysis.

Contribution

It introduces a comprehensive global model unifying seismic, tectonic, and fluid dynamics in Earth's layers with rigorous mathematical validation.

Findings

Model captures seismic wave behavior across Earth's layers.

Couples seismic sources with wave propagation automatically.

Provides mathematical proof of solution existence and energy conservation.

Abstract

The philosophy that a single "monolithic" model can "asymptotically" replace and couple in a simple elegant way several specialized models relevant on various Earth layers is presented and, in special situations, also rigorously justified. In particular, global seismicity and tectonics is coupled to capture e.g.\ (here by a simplified model) ruptures of lithospheric faults generating seismic waves which then propagate through the solid-like mantle and inner core both as shear (S) or pressure (P) waves, while S-waves are suppressed in the fluidic outer core and also in the oceans. The "monolithic-type" models have the capacity to describe all the mentioned features globally in a unified way together with corresponding interfacial conditions implicitly involved, only when scaling its parameters appropriately in different Earth's layers. Coupling of seismic waves with seismic sources due to tectonic events is thus an automatic side effect. The global ansatz is here based, rather for an illustration, only on a relatively simple Jeffreys' viscoelastic damageable material at small strains whose various scaling (limits) can lead to Boger's viscoelastic fluid or even to purely elastic (inviscid) fluid. Self-induced gravity field, Coriolis, centrifugal, and tidal forces are counted in our global model, as well. The rigorous mathematical analysis as far as the existence of solutions, convergence of the mentioned scalings, and energy conservation is briefly presented.