The philosophical framework:

A knowable material reality with necessities, but also with possibilities and potentialities, exists independent of human thought and action.

Questions to answer:

• Is the dominant character of processes inside the Earth reversible or irreversible?

• If irreversibility dominates, is it degrading or upgrading?

• If upgrading, is it a result of one major catastrophic event that happened very early in Earth’s history, or is it an ongoing process and a result of many episodes?

• Is the Earth a Heat Engine (Gravity mechanics) or a Stress Engine(Quantum mechanics)?

Some cognitive tools from Physics:

• Reversibility, that is the return to the original values of thermodynamic variables, requires:

a)  Thermal equilibrium, that is slow change so that all thermodynamic variables are well defined at all times and their return to their original values is possible by reversing the external conditions.

b)  The action of conservative forces, that is path and time independent forces, i.e., gravity, and the absence of non-conservative forces, i.e., friction.

c)  Independent particles, i.e., ideal or very dilute gases.

d)  No heat loss to the environment (insulation and/or very fast change).
 

• Irreversibility, that is the conversion of some of the kinetic energy into heat, and the impossibility of return to the original values, is a result of :
 
a)  Lack of thermal equilibrium, that is fast change so that the thermodynamic variables are not well defined at all times.

b)  Non-conservative forces, that is path and time dependent forces, i.e., friction.

c)  Interaction of particles, i.e., real gases, fluids.

d)  Lack of insulation.
 

• Thermal energy, that is the sum of translational, rotational and vibrational energy is only a very small fraction, of the order of 10^-4 to 10^-5, of electronic energy.

• Entropy, S, is a measure of the amount of the disorder in a thermal system. Like thermal energy, is a function of state, and only changes in entropy have physical significance. Entropy changes are path independent. For infinitesimal reversible transformations, dS º dQ/T.

• For ideal gases entropy, that is disorder, decreases as temperature decreases :

• In a thermally isolated-closed system reversibility, that is the lack of changes in entropy (dS/T = 0), is possible because S(B) - S(A) ³ 0.

• In a thermally open system complete reversibility is impossible, that is dS/T< 0 and S(B) - S(A) < 0.

• Therefore in the real world complete conversion of thermal energy into mechanical work is impossible, without any further effect. In other words complete reversibility is impossible, unless there is a constant input of thermal energy.

• The effect of pressure on the entropy of a crystal can be expressed by the formula S = klnW, where k Boltzmann’s constant (1.38´10^-23 J/K) and W the probability of realization of various lattice arrangements or degrees of freedom. In other words the higher the pressure, the stronger the restriction of the mobility of atoms, the fewer the degrees of freedom and the smaller the probability of realization of various lattice arrangements, and consequently the lower the entropy.

• For ideal or very dilute gases PV/n = RT, where P, pressure, V, volume, n, number of moles, T, temperature, and R = 8.314 J/mol K.

• Ideal fluids are :
 
a)  frictionless,

b)  incompressible,

c)  their density is constant, in time and space, that is they are homogeneous and isotropic

d)  the exerted force is pressure independent. In other words the particles of an ideal fluid move about with complete freedom.

• In real fluids the particles move with restricted freedom.

• Newton’s theory of gravitation (U = GMm/r) refers to bodies that move with speed u<<c, and there is nothing between them, i.e., no field, is a limiting case of Einstein’s general theory of relativity (U = m.c²) and of the equivalence principle that introduces the notion of the field and explains gravitation in terms of distortion-curvature of space.

• The equivalence principle states that no experiment can distinguish between:

• The special theory of relativity is based on two postulates :
 
1)  The laws of nature are the same in all frames of reference in relative motion at constant velocity, that is there are no objects that are ‘really stationary’ and others that are ‘really moving’.

2)  The speed of light in empty space has the same value to all observers, regardless of their state of motion, that is the velocity of light is the same regardless if the observer is stationary or moving. In other words, according to that postulate, no
material body can reach the speed of light, because if it does it will be at rest in
respect to light, therefore it would cease to exist. But the nothing is nonexistent.

• According to Maxwell’s equations for the propagation of electromagnetic waves:
 
1)  The universe is not empty but it is filled with the stationary ether.

2)  The electromagnetic waves travel with the speed of light, c, relative to the
ether’s rest frame. If an observer is moving at a speed, u, relative to the ether, the
speed of light emitted by a source at rest relative to the ether would be c+u if the
observer were moving toward the source, and c-u if the observer were moving
away from the source. The ether is the matter, the energy, and the energy fields
that fil and transverse space and time. Empty space-absolute vacuum, does not exist.

• For real gases, the Van der Waals equation ¾[P + a(n/V)²][(V/n - b)] = RT, where a and b are positive constants ¾ states that the attractive component of the intermolecular force acts to make a gas more compact. This translates into reduced pressure, and the a(n/V)² term represents the pressure reduction due to attraction between molecules. The term b represents the strong repulsion between molecules at a characteristic radius, and is a measure of volume unavailable for motion.

• Under high pressure, change of position, that is translation, rotation and vibration of atoms, is negligible to nonexistent, and the heat capacity of the system is very low.. The electronic energy level involves great amounts of energy, the compression of electron shells and the flow of electrons and of other particles, that is high electrical conductivity.

• Thermal energy, that is, in increasing order, translational, rotational and vibrational energy is only a very small fraction, from 10^-6 to 10^-2, of electronic energy.

• The binding energy between atoms is of the order of eV, while between nucleons is of the order of MeV, that is about 10⁶ times greater. Iron has the highest binding nuclear energy, 8.8 MeV per nucleon, from all elements, and hydrogen the lowest, 1.1 MeV per nucleon.

• The gravitational force between a proton and an electron is only ~4´10^-47 N, while the electric force is ~9´10^-8 N, that is ~10³⁹ times greater than the gravitational force.

• The electric force is behind friction and other contact forces.

• The size of a mineral is of the order of 10^-5 m, of an atom 10^-10 m, of a proton and a neutron 10^-15 m and of an electron less than 10^-18 m.

• The mass of a nucleon (proton or neutron) is about 1.67´10^-27 kg and that of an electron 9.1´10^-31 kg.

• The electric charge of an electron and of a proton is - 1.6´10^-19 and +1.6´10^-19 Coulomb, respectively.

• Tunneling, that is the crossing of a potential barrier, can occur either by increasing the kinetic energy of particles through heating, at 10⁶ to 10⁹ degrees, and/or by lowering the barrier height by applying an external electric potential, i.e., van der Waals dielectrics, and/or by decreasing the barrier width, at 10^-8 to 10^-9 m, through pressure. For fusion of H nuclei to occur a pressure of the order of 10²⁶ Pa is required.

• For two protons that fuse with two ²H nuclei to form two ³He nuclei, that in turn fuse to produce one ⁴He nucleus, two protons and 24 MeV are produced. (2²H + 2p ® 2³He + 2g + 11 MeV ® ⁴He + 2p + g + 13 MeV)

• Van der Waals attractive forces (1/r⁵), are weak when compared to coulombic attractive forces (1/r²), develop when atoms without electrons outside closed shells acquire polarity and form molecules with a subsequent contraction-condensation and reduction in pressure, i.e., helium molecules (He₂).

• Dipoles are formed when two equal point electric charges - electric dipoles or magnetic poles - magnetic dipoles of opposite sign do not coincide, and are separated by a small distance.

• Electric and magnetic dipoles produce a field and respond to a field.

• Dipole moment of a particle is the product of either charge or pole and the distance between the two. It is a measure of its electrical and/or magnetic asymmetry.

• Polarity can be intrinsic or induced as a result of external electric field and/or pressure. For that matter attractive forces, due to polarity, can develop among any polar-spinning particles, i.e., between nucleons.

• The greater the pressure the greater the polarizability of particles.

• Dipole orientations favor the attractive low potential energy over the repulsive high potential energy.

• Van der Waals forces that develop between dipoles themselves and between dipoles and the walls of a confining material, are much stronger than the force of gravity (i.e., ~10³⁶ times) and they can move the polar atoms against gravity.

• Capacitors are a pair of conductors with equal but opposite charges separated by empty space or by a non conducting material, i.e., dielectric.

• Dielectrics, that is polar atoms attracted by van der Walls forces, behave as insulators, that is the net electric field inside the dielectric, E, is equal to the external electric field, E₀, minus the induced electric field, E_ind, E = E₀ - E_ind.  If E_ind were to exceed E₀, that is the dielectric-insulator to become a conductor, due to the addition of electrons in outer shells, the electric field inside the dielectric will be reversed.

• Dielectric and diamagnetic substances develop an induced electric and magnetic field, opposite to the direction of the inducing electric or magnetic field, respectively. They behave as electric and magnetic insulators. For example, inert gases such as helium, neon and argon but also iron with filled the 3d-level with 10 electrons.

• The electrical conductivity of an insulator (i.e., glass) is from 10^-14 to 10^-10 (ohm-meters)^-1, of a semiconductor (i.e., silicon, carbon) from 10^-3 to 10⁵ (ohm-meters)^-1, of a conductor (i.e., iron, aluminum, copper, silver) from 10⁷ to 10⁸ (ohm-meters)^-1 and of a superconductor over 10⁸ (ohm-meters)^-1.

• The estimated electrical conductivity ranges from ~10^-2 in the surface, to ~10^-3 in old shields, to ~1 in young oceans, to ~ 10² (ohm-meters)^-1 at the core-mantle boundary.

• A superconductor behaves as diamagnetic material, that is no magnetic field can penetrate it.

• Inside a Type I superconductor the electric and the magnetic resistivities are zero, that is the electric and the magnetic fields inside it are zero.

• Inside a Type II superconductor the electric and magnetic resistivities are not zero, that is the electric and the magnetic fields inside it are not zero, but they are zero on its surface. In that case all current carried by a superconductor is carried on its surface, which represents the boundary between the superconducting and the nonsuperconducting phase of the material.

• An electron in an atom moves with a speed of the order of 10⁶ m/sec, while a free electron in a TV tube travels with a speed of 7´10⁷ m/sec.

• Experimental values show and quantum physics predicts that:
 
a)  The mean free path to be about two orders of magnitude greater, and the mean
collision time about one order of magnitude longer and the average speed one order
of magnitude greater than the free-electron, temperature dependent, classical
prediction.

b)  In a perfectly ordered crystal with no impurities, at the temperature of zero, there would be no resistance to electron flow, and conductivity would be infinite.

• Electrical conductivity is inversely proportional to temperature, that is to the increased vibration of lattice atoms and proportional to pressure.. Even in semiconductors, tunneling and, therefore, increase in conductivity can occur by narrowing the energy gap by compression and/or by applying a modest electric field and only in a low pressure environment heat can excite electrons and ions.

• Angular momentum, L = Iw , of a particle is the product of moment of inertia, I=mr², and angular velocity, w = u/r, has the dimensions of action (energy-work ´ time), kg.m².s^-1.

• Planck’s constant, h = 6.63´10^-34 J.s, relates the frequency of radiation, f, with its quantum of energy, E; i.e., E = hf. It has the dimensions of action , that is of angular momentum.

• Quantum numbers are integral or half-integral multiples of h/2p that specify the energy state of a system in quantum mechanics. An electron has four quantum numbers.
 
a)  The principal quantum number, n = 1,2,3 ,..., defining the energy level or shell in
which the electron occurs,

b)  The azimuthal quantum number, l = 0, 1, 2, ..., n-1, defining the shape and the
multiplicity of the orbit within that shell,

c)  The magnetic orbital quantum number, m_o = -l -l +1,..., 0,..., l -1, l, which
determines the orientation of the orbit, with reference to a strong magnetic field, and,

d)  The magnetic spin quantum number, m_s = ± ½ , which determines the direction of the spin of an electron in a magnetic field. The + or - stand for clockwise or
anticlockwise direction of rotation or spinning, respectively.

• The angular momentum of a particle has two components. The orbital (n and l-magnitude, and m-direction) and the spinning (s-direction).

• The orbital magnetic dipole moment, m_o = m_bl , can have values that are integral multiples of Bohr magneton, m_b = eh/4p m_e .

• Magnetic field lines, that is the magnetic dipole moments, form circles around the moving electric charge or current in a plane perpendicular to the moving charge or current.

• Magnetism in mater is due ultimately to the magnetism of its atomic constituents, and particularly to the unpaired electrons of atoms.

• If two orbiting electrons have opposite directions, i.e., clockwise-anticlockwise, the orbital magnetic dipole moment, in the absence of an external magnetic field, is zero.

• The zero (0,­¯) spin state, due to the attractive forces between particles with spins in opposite directions, is a low energy state.

• The unit (+1­­, -1¯¯)spin state, due to the repulsive forces between particles with spins in the same direction, is a high energy state.

• Particles with unit spin can be oriented along any applied field to give the three states with quantized integral spin components, i.e., +1(­­), 0(­¯), - 1(¯¯).

• The nuclear spin quantum number can be 0 or integral or half-integral number.

• Bosons are particles with total spin zero or integral multiple of h/2p : I_b(h/2p), where I_b= 0, ± 1, ± 2, ± 3,...± n.

• Fermions are particles with total spin half-integral multiple of h/2p : (I_b+ ½)(h/2p).

• The Pauli exclusion principle states that only one boson with identical zero or integral spin and only up to two fermions with identical half-integral spins, can occupy the same energy state, i.e., have the same n, l and m_o quantum numbers.

• According to Heisenberg’s uncertainty principle in any quantum phenomenon (particle - wavelike phenomenon) at any given time it is impossible to know precisely both the position and the speed-momentum of the particle.

• Identical bosons tend to congregate in the same, lowest possible, energy state. This can explain laser-maser (Light/Microwave Amplification by Stimulated Emission of Radiation) and superfluidity.

• Pairs of identical fermions, i.e., electrons, can form bosons with a net angular momentum of 0 or integral multiple of h/2p , and behave like a large system of identical bosons. That is the microscopic explanation of superconductivity.

• Incompressibility is a result of repulsive forces (coulombic and between identical fermions, i.e., electrons). Measure of incompressibility is the bulk modulus (N/m²), that is the ratio between volume stress and volume strain (PV/dV).

• Compressibility is a result of attractive forces that develop between identical bosons as well as of coulombic attraction. Measure of compressibility is the negative (contraction due to attraction) reciprocal of bulk modulus(m²/N).

• Degeneracy pressure, P_e , is the outward directed pressure, due to electrons. It is another expression of the incompressibility of matter. It is calculated according to the formula:

• Gravitational pressure, P_g , is the inward directed pressure, due to neucleons, that acts to compress matter. It is calculated according to the formula :

• Resonance is the result of congregation of identical bosons and/or of pairs of fermions.

• Shock waves, that is a very narrow region of high pressure and energy, are produced whenever wave sources, i.e., electrons, protons, a-particles, can move faster than the waves they produce. The higher the speed of the particle, the sharper the cone of the shock wave (q₀®90⁰) that tends to become a line and, therefore, the higher the pressures in the medium and the more abrupt the change in that. A proton travelling with a speed of the order of 3´10⁷ m/sec produces shockwave pressures of the order of 10³⁰ Pa.

• Superconductivity, that is the pairing of fermions into bosons, i.e., pairing of electrons, as far apart as 10^-7m, that is about 10¹¹ times their size, occurs because of the presence of other pairs in the same energy state. Pairs condense, and behave as one coherent ‘solid’ state, when ion lattices can not vibrate, as a result of low temperature and/or high pressure.

• ⁴He atoms, are bosons with 0 angular momentum for the nucleus (two protons and two neutrons) and 0 or integral multiple of h/2pfor the two electrons (± 1/2 , ± 1/2). Therefore they are subject to the exclusion principle and they condense into a coherent state. They exhibit superfluidity, that is they flow as if they have no internal friction (no viscosity).

• For a given potential energy of a particle, the smaller the region in space that is made available to the particle, that is the higher the pressure, the higher will be the kinetic and, therefore, the total energy of the particle.

• The core of the Earth can be considered as a real gas of particles, particularly of electrons, protons and a-particles, subject to the exclusion principle. The real gas character is mostly due to polarity and to the attractive, van der Waals forces, that tend to make them cluster. The volume occupied by the particles is negligible and, therefore, the excluded volume correction is also negligible. On the other hand the pressure reduction correction, due to clustering, is very important, resulting into a considerable contraction-reduction in volume.

• Plasma is matter dissociated into positively and negatively charged particles, and it is considered as the fourth state of matter.

• There are three fundamental forces:
 
1.  Gravity that refers to bulk matter,

2.  Weak Force that includes all electromagnetic type forces and refers to the atomic level, and,

3.  Strong Force of the nuclear level.

• On all but the astronomical scale, atomic and nuclear forces are much stronger than gravitational forces.

• So far a theory that unifies gravity mechanics-general relativity and quantum mechanics-uncertainty principle has not been found.

• 60 to 65% of the Earth’s surface is covered by oceanic crust, that is rocks mafic in composition and younger than 200 m. y.

• 35 to 40% of Earth’s surface is covered by continental crust, that is rocks intermediate to felsic in composition and up to 4 b.y. old.

• The composition and the age of rocks in other planets, i.e., Moon, Mars, Mercury, meteorites, is similar to rocks of the continental crust of the Earth, that is, they are iron poor and about 4 b.y. old. Iron rich rocks are scarce and are much older than 200 m. y.

• The northern hemisphere is about 2.5 km higher than the southern hemisphere. As a result its moment of inertia is greater by 0.03%, or by 1.25´10⁴⁰ gr/cm² and it is lagging westward relative to the southern hemisphere (Tethyan Torsion).

• Isotope composition of most granitic batholiths indicates an origin in the lower crust or upper mantle.

• The geothermal heat loss of the Earth is of the order of 3´10¹³ W per year.

• The heat flow from both continental and oceanic areas is of the order of 1.5 - 2 m cal/sec/cm² (HFU) or 60 - 80 mW/m².

• The concentration of ²³²Th and ²³⁸U in the Earth is 65 and 18 ppb, respectively.

• Almost all radioactive elements are concentrated at the upper few kilometers of the Earth’s continental crust.

• The concentration of radioactive elements in the Moon is about three times greater than in the Earth.

• The gravitational field of the Earth is about 980 gals ± 0.5%.

• Gravity fluctuations are usually of the order of few mgals to few hundred mgals = 10^-6.

• Bouger gravity anomalies measure past or present density differences from an assumed average density for a given area.

• Free-air gravity anomalies measure contemporary or very recenttopographical differences -uplift, i.e., differences between the geoid and the sheroid-ellipsoid.

• The electric field on the Earth’s surface is of the order of -10² Volts/meter (Newtons/Coulomb).

• The estimated potential difference between the surface of the earth and the mantle-core boundary is 290´10⁶ Volts.

• The assumed electric field at the mantle -outer core surface is of the order of -10³¹ V/m. That corresponds to a charge of ~10⁵³ electrons.

• The assumed electric field at the outer core-inner core boundary is of the order of +10²⁹ Volts/meter. That corresponds to a point charge of about 10⁵⁰ protons in the inner core.

• The assumed potential difference between the mantle-outer core boundary and the outer core-inner core boundary is of the order of 2´10³⁷V.

• Almost all rock-forming minerals are compounds which have mixedionicandcovalent bonding and they are fundamentally electrical insulators, with conductivity, in their pure ‘dry’ crystalline form, of the order of 10^-12 to 10^-17 mhos/m.

• Moisture and water in minute cracks can conduct electricity by electrolytic transport and increase the conductivity of ‘dry’ crystals up to 10¹¹ times.

• Metallic minerals, that is minerals that share the outer electrons of the metallic atoms, i.e., pyrite (FeS₂), pyrrhotite (FeS), galena (PbS), graphite (C), etc., have conductivities that range between 10² and 10⁶ mhos/m.

• Native metals, i.e., iron, copper and silver, are excellent conductors, with conductivities 5´10⁶, 5.8´10⁷ and 6´10⁷ mhos/m, respectively.

• The Earth is a weak magnet and the strength - intensity of its magnetic field, 0.35 - 0.65 oersted (~9 to 16 Amp/m), corresponds to a magnetic dipole of moment 8´10²⁶ emu or 2´10²² Amp/m² , of a magnet which is situated close to its center and is inclined at about 11⁰ to the geographical axis.

• The magnetic flux density is about 0.5 Gauss (in S.I. units 0.5´10^-4 Tesla).

• The practical unit for measuring magnetic field strength is the g (gamma) = 10^-5 oersted.

• The average magnetic intensity is about 50,000 gammas. The maximum polar intensity is 65,000 gammas and the minimum equatorial intensity 35,000 gammas.

• In a number of cases magnetic anomalies having amplitude higher than 100,000 gammas have been recorded on the ground over magnetite deposits. That is up to three times the amplitude of the Earth’s magnetic field.

• All materials are diamagnetic, that is when placed in a magnetic field they will acquire a small magnetic moment which is in a direction opposing the field. The diamagnetic effect is, in fact, temperature independent and is a function of the quantum numbers of the electrons, i.e., it depends on the nature of the electron orbitals..

• Many materials are also paramagnetic, that is when placed in a magnetic field they will acquire magnetization which is proportional to, and in the same direction as the external field.

• Truly ferromagnetic are those materials that the magnetic moments of all the ions in the lattice tend to point in the same direction, i.e., metallic iron, nickel, cobalt.

• In ferrimagnetic materials some of the moments tend to lie in a direction different to opposite from that of the others, i.e., magnetite (Fe₃O₄).

• Antiferromagnetic is a special case of ferrimagnetic material, whereby the ions of the lattice are divided into two exactly equivalent groups, which are magnetized in opposite direction, i.e., hematite (Fe₂O₃).

• Magnetic susceptibility is the ratio of intensity of magnetization produced in a substance to the strength of the magnetic field to which it is subjected.

• At multidomain grains, and for grain sizes bigger than ~10^-5 m, i.e. Fe₃O₄, the magnetic susceptibility increases with increasing size.

• For grain sizes smaller than about 10^-5 m and bigger than about 10^-6 m, the magnetic susceptibility decreases with decreasing grain size, i.e., the smaller the size, the weaker the induced magnetization by a given external field and the stronger the residual magnetization when that field is removed.

• In monodomain grains, and for grain sizes less than 10^-6 m, the magnetic susceptibility increases with decreasing size while hysteresis effects diminish. A material at such stage is said to be superparamagnetic.

• In monodomain grains the energy barrier, between the different directions in which the magnetization is stable, is high. Therefore a strong field is required to produce change, and once changed, the magnetization does not easily return to its original state.

• The magnetic susceptibility of mafic rocks, i.e., basalt, is about 3´10^-3 emu, while of felsic rocks, i.e., granite, is about 0.5´10^-3 emu.

• The magnetic flux density of an electron that moves with a speed of 10⁷ m/sec at the mantle-core boundary and around the inner core, where about 10⁵⁰ protons are present, is of the order of 10²¹ Tesla.

• Magnetic reversals need a few thousand years to happen and, on the average, they last about 500 thousand years.

• Moon, Mars and Mercury have very weak remnant or no magnetic field.

• An increase of radius and/or of mass in a zone of a spinning body will result to an increase of its moment of inertia (I = m.r²) and consequently of the centrifugal force - torque (F = t = I.a = m.r².v²/r = m.r.v²) of that zone which will tend to become equatorial.

• Orogenic episodes reached their maximum intensity at 2600, 1800, 900 (Cordilleran), 500 (Caledonian-Hercynian), and 100 (Alpine) million years ago.

• The non-elastic brittle deformation is rapture-faulting, and the non-elastic ductile deformation is flow-folding.

• The faulting in the crust is, in general, normal. It is a result of tensional fracture at the surface and shear fracture at greater depths.

• In normal faults the maximum principal stress is vertical, i.e., gravity.

• At the flanks of domed-deformed areas, the faulting is reverse.

• In reverse faults gravity is the minimum principal stress.

• In strike-slip faults gravity is the intermediate principal stress.

• In oblique-slip faults none of the principal stress axis is vertical.

• In Benioff zones the faulting is reverse and oblique.

• Brittle-plastic substances, when their strength is not exceeded, undergo cataclastic flow-transient creep, which results to deformation up to ~1% and it is due to repeated shear fractures which progressively reduce the grain size, or to the rolling and sliding of fragments over one another.

• Ductile deformation, that is flow, occurs when the strength of a brittle-plastic substance is exceeded or when the substance has low viscosity, i.e., it is fluid. It can be:
 
a)  a low temperature plastic flow, in which gliding motions on intersecting planes occur, and the material behaves as a plastic-brittle substance.

b)  power-law flow or creep, caused by motion on dislocations which take up a polygonal cellular pattern within the grains, and

c)  diffusion creep, caused by migration of atoms in a stress gradient, occurring within the crystal lattices or along grain boundaries.

In all cases the flow can be temperature independent and pressure dependent.

• In passive folds, the viscosity of each layer is the same or nearly the same, and each layer has a similar folded form.

• Flexural-slip folds commonly become detached, due to differences in viscosity, along some surface at depth, called the décollement zone, which is a low viscosity zone.

• A Newtonian fluid is a viscous fluid in which the viscous -shear stress, t (gr/cm.sec² or kg/m.sec²), is a multiple of the rate of strain, (DL/L)/dt - velocity gradient, du/dy (sec^-1), and of the constant of proportionality, that is the fluid viscosity, m (gr/cm.sec, or kg/m.sec) [t= m (du/dy)].

• In a non-Newtonian, visco-elastic, fluid the shear stress depends not only on the velocity gradient, but also on the strain.

• A plastic-brittle material exhibits an apparent yield stress (t). In other words it behave as a solid, that is its strain rate is very low and remains low as the shear stress increases until it yields and as the shear stress further increases, it behaves like a viscous fluid, that is for low shear stress its strain rate is very high.

• Superplastic flow occurs when there is a significant concentration of a mineral phase of very small grain size, i.e., of atomic dimensions.

• A dilatant-ductile material behaves as a low viscosity fluid at low stress and strain rates, but as solid as the stress and strain rate increase.

• In a Stress Engine Earth the interior of the Earth, i.e., the mantle, behaves like a plastic-brittle material, while in a Heat Engine Earth as dilatant-ductile material.

• The strain-creep rate, that is the velocity gradient inside the Earth is of the order of 10^-15 sec^-1, that is a velocity of flow of the order of few centimeters per year and a boundary layer of the order of 100 to 1000 km, whereas the slowest rates attainable in experiments is only about 10^-8 sec^-1, that is about 10⁷ times faster.

• Experiments show that for pressures above ~0.5 GPa, that is for depths greater than ~20 km, and for temperatures above 770 K, that is above 500 ⁰C, no brittle deformation, that is no sudden fracture, occurs.

• The strength of brittle materials increases with the increase of the confining pressure but decreases with rise of temperature.

• The strength of ductile materials decreases with the increase of the confining pressure and of the temperature.

• At atmospheric temperature and pressure the tensile strengthof granite is ~10⁶ Pa, while its compressive strength is ~1.4´10⁸ Pa.

• Tensile strength of rocks in the mantle is of the order of 10¹⁰ Pa, while the compressive strength is of the order of 10¹¹ Pa.

• The rigidity and the incompressibility of rocks in the crust is estimated to be of the order of 5´10¹⁰ and 10¹¹ Pa, in the upper mantle 10¹¹ and 2´10¹¹ Pa, in the lower mantle 2.5´10¹¹ and 5´10¹¹ Pa, in the outer core 0 and 10¹² Pa, and, in the inner core 1.8´10¹¹ and 1.5´10¹² Pa, respectively.

• The viscosity of rocks inside the Earth is estimated to be from 10²⁰ to10²⁷ poises.

• The relaxation time (viscosity/rigidity) for rocks inside the Earth is of the order of 10⁹ to 10¹⁵ sec, that is of the order of tens of years to tens of million years.

• The duration of applied stresses inside the Earth is from less than 1 second to over 10¹⁶ seconds, that is billion years.

• In island arcs the potassium content increases proportionally to the depth of the Benioff zone.

• The Q factor for P and S waves in the crust and in the upper mantle is estimated to be of the order of 300 - 400 and 100 - 150, in the lower mantle 5000 and 2000, in the outer core 10000 and 0, and, in the inner core 900 and 500, respectively. In other words, in the outer core, the attenuation is extremely low for P waves and extremely high for S waves.. In the lower mantle attenuation is very small for both P and S waves, while in the upper mantle and in the crust is relatively high.

• When the dimensions of flow are equal or greater than the length of seismic waves, mainly of S waves, that transverse the flow, the seismic waves can ‘see’ and ‘feel’ the flow and the peak or the valley of the wave that has the same direction with the flow is absorbed by it, thus increasing the rate of flow and, consequently, the attenuation.

• Temperature increase can increase attenuation by decreasing resistance to flow.

• The velocity of P and S waves in the upper mantle is estimated to be of the order of 8 and 4.5 km/sec, in the lower mantle 12 and 5 km/sec, in the outer core 10 and 0 km/sec, and, in the inner core 11 and 3.5 km/sec, respectively.

• The average density of the crust is ~2.8 gr/cm³, of the mantle ~4.5 gr/cm³ , of the core ~10.7 gr/cm³, and of the whole Earth ~5.5 gr/cm³.

• The pressure at the crust - mantle boundary is of the order of 10⁹ Pa, at the mantle - core boundary is ~1.4´10¹¹ Pa, and, at the center of the Earth ~3.7´10¹¹ Pa.

• The variation with depth of seismic wave velocities, of density, and of pressure is known with a degree of confidence of 95%.

• The variation of temperature with depth, for depths greater than about 10 km, is not directly known.

• The dominant character of processes inside the Earth is irreversible.

• The irreversibility is upgrading.

• The upgrading irreversibility is a result of many episodes.

• The Earth, except for a thin surface layer, is a Stress Engine--that is, an electrically unbalanced ‘real gas’ of particles subject to the exclusion principle.

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