Advances in Conception about Earthquakes - Earthquake Engineering for Structural Design - page 118

Figure 4.10 Behavior near and far from equilibrium (Gioncu, 2005)
replaced by the idea of continental mobility, due to the convection in the mantle
(Anderson, 2003) (see Chapter 2, Figure 2.1). Scientists today generally agree that
the plate-driving forces result from the hot softened mantle which lies below the
cold rigid plates. So, both the Earth's surface and its interior are in motion.
Circular motion of the mantle carries the plates in the direction of rotation.
The Earth's surface is covered by about twelve large tectonic plates which
relatively move each other and respect the underlying mantle. The plate tectonic
can be considered as a successful example of a far-from-equilibrium self-organized
system, powered by heat (as an external source of energy) and gravity from the
mantle and organized by dissipating in and among the plates (Anderson, 2001a).
Figure 4.11 shows a cross-section of the Earth, where the equilibrium between the
sea-floor spreading in the Mid-Atlantic and East Pacific Rise is equilibrated by the
subduction in the East and West Zones of Pacific Ocean, forming a self-organized
system among plates and mantle convection. The surface plates are the active
element, the convicting mantle is the passive element.
When a tectonic plate is placed on the convecting system, it organizes the
convective flow and the plates themselves become a dissipative self-organized
system.