SOLID EARTH GEOPHYSICS AND GEOTHERMICS

The course has the stated goal of providing adequate knowledge and understanding of the Solid Earth Geophysics for the characterization of dynamics and internal structure of the Earth and for the assessment of seismic hazard and risk; the seismic classification and the seismic code of the national territory. It also wants to propose a means of finding alternative geo-resources, such as geothermal energy.

Methods for determination of constitution and distribution of masses within the Earth.
The Earth in the Solar System. Dynamics of planets. Characteristics and origin of the planets of the solar system. Earth's rotation. Angular momentum and inertia. Earth tides. Changes in the Earth's rotation. Redistribution of momentum in the Earth and the distribution of masses inside. Euler nutation and the Chandler wobble. Precession and forced nutation. Dynamical ellipticity of the Earth. Milankovitch climatic cycles.
Wave propagation inside the Earth. Surface waves. Phase and group velocity. Scattering of surface waves.
Free oscillations of the Earth. Vibration modes of the Earth: spheroidal and torsional oscillations. Applications of free oscillations for the definition of the structural model of the Earth.
Theory of gravitational and magnetic fields. Potential fields. Laplace's equation in Cartesian and spherical coordinates. Solutions of Laplace's equation.
Earth's gravitational field. Variations of the field. Representation in spherical harmonics. Spheroid and geoid. Acceleration of gravity.
Earth's magnetic field; representation of c.m.t.; variation of c.m.t.; origin of c.m.t. Magnetization of the rocks; reconstruction of the magnetic poles; paleomagnetism. Magnetic anomalies; interpretations of magnetic anomalies.
The internal heat of the earth: the radioactivity as a heat source, heat production from the rocks; description of the internal structure of the earth; propagation of heat in the earth (by conduction, convection and radiation). Concept of temperature, specific heat and thermal gradient. Geothermal gradient; construction of the geothermal curve based on petrological and geophysical data.
The heat flow in the continents: determination of the different contributions of the different sources of heat, determination of the layer of granitic continental crust, identification of geologically active provinces. The heat flow of the ocean: distribution of heat flows and comparison with the heat flows in continental areas.
The sublithospheric mantle. Nature of the asthenosphere. Properties of the mantle. Methods for calculating the density of the mantle: Adams and Williamson equation, the Monte Carlo method of Press. Pressure, gravity, elastic properties of the mantle. Mineralogical composition of the mantle.
Heterogeneity of the mantle on a regional scale. Rheology of the Mantle . Convective motions in the mantle. Vertical development of convection. Geophysical evidence of convection in the mantle. Areal distribution of convective cells.
Core-mantle transition. General characteristics of the core. Transition outer core - inner core, layer F. Composition of the core. Thermal state of the core. Convection in the outer core and Earth's magnetic field .
Forces acting on lithospheric plates: forces driving and resisting the movement; magnitudes of the forces . Mechanism. Mechanism of marginal forces .
Geophysical characteristics of the different plate boundaries. Stress distribution along the margins and focal mechanisms of earthquakes. Distribution of volcanism. Hot Spot.
Geodynamics of the Mediterranean area. Geodynamic models of the Italy. Distribution and focal mechanisms of earthquakes in the Italian area.
Seismic classification of the national territory.
Definition of seismic risk: hazard, vulnerability, exposure value. Deterministic and probabilistic methods. Method of extreme value of Gumbel; Method of Cornell. Hazard calculation from the observations at the site. Elements for the definition of seismic hazard. earthquake catalogues. Historical events parameterization. Attenuation laws. Seismotectonic and seismogenic models : useful elements for the definition of seismogenic zones .
Effects of earthquakes. Direct and indirect phenomena.
Macroseismic scales: from the Rossi- Forel scale the modern MM , MCS, MSK , EMS 98 scales. Building types and vulnerability. Damage levels and percentage of damage. Estimation of intensity. Application to the Italian area.
Indirect effects caused by earthquakes: seismic hazard scenarios .
Paleoseismology: seismites and paleoseismites. Genetic categories. Surface faulting, capable faults and seismogenic structures . Examples of paleoseismological data use: American and Italian cases.
Tsunami. Mechanisms of tsunami generation. Propagation of tsunamis. Run-up. Magnitude. World distribution of the tsunami. Pacific, Atlantic, Mediterranean area. The risk from tsunamis in Italy. Tsunamis in Sicily in 1693 and 1908.
Seismic scenarios. Historical evolution of the city of Catania as a result to natural disasters: earthquakes and eruptions .
Seismic code in Italy: history, current legislation .
Geothermal fields: geological and structural conditions for their existence, the dynamics of geothermal fluids and their physical condition; temperature distribution within the productive layer and cups; definitions of the various geothermal manifestations .
Types of geothermal systems: recent igneous systems, tectonic systems, geopressured systems, dry systems. Heat flow, geothermes and the role of magmatic systems. Conceptual models of geothermal systems: vapour-dominated, liquid-dominant systems. Physical and chemical characteristics of hydrothermal fluids: gas, vapour and liquid. Surface manifestations of geothermal systems. Role of the geological structures in the definition of geothermal fields and defining the boundaries of the tanks. Geological, geophysical and geochemical methods for geothermal researches.
Thermodynamic conditions of the geothermal steam in the extraction process: isoenthalpic expansion, enthalpy - entropy diagram .
Use of geothermal resources: direct and indirect use. Low-enthalpy systems: civil and industrial uses (e.g. in agriculture and manufacturing). High enthalpy systems: production of geothermal energy. Extraction (wells), transportation (steam pipelines) and geothermal power. Types of power plants. Practical examples of geothermal exploration. Utilization of geothermal resources.
Geothermal energy and the Environment: Sources of pollution. Risks related to geothermal energy. Examples from leading Italian and geothermal fields in the world. Power plants.

Gasparini P., Mantovani M.S.M., 1981. Fisica della Terra solida. Liguori editori.
Lowrie W., 1997. Fundamentals of Geophysics. Cambridge University Press.
Fowler C.M.R., 1990. The Solid Earth. An introduction to Global Geophysics. Cambridge University Press.
Kearey P., Frederick J.V., 1994. Tettonica Globale. Zanichelli editore.
Sommaruga C. e Verdini G. (1995). Geotermia. Principi, ricerca, produzione. NIS - La Nuova Italia Scientifica, Roma, 189 pp.