GEOFISICA DELLA TERRA SOLIDA CON LABORATORIO

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.

42 hours of lectures and 36 hours of work with exercises and educational excursions

If the teaching is given in a mixed or remote mode, the necessary changes with respect to what was previously stated may be introduced, in order to respect the program envisaged and reported in the syllabus.

Not obligatory but recommended passing the exams of Mathematical Methods and Seismology. Some of the topics covered recall concepts developed in these classes.

Attendance to the course is obligatory for at least 70% of the lessons. However, it is suggested to attend most of the lessons, because basic concepts are also recalled in the classroom that are not strictly related to the program but preparatory to understanding the topics covered.

Information for students with disabilities and / or SLD: To guarantee equal opportunities and in compliance with the laws in force, interested students can ask for a personal interview in order to plan any compensatory and / or dispensatory measures, based on the didactic objectives and specifications.

It is also possible to contact the referent teacher CInAP (Center for Active and Participated Integration - Services for Disabilities and / or SLD) of our Department, prof. Giorgio De Guidi

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. 
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 
 

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.
 

The final exam takes place in oral form and may include written or practical tests, both in progress and during the exam sessions, on the topics covered. The student can also prepare a power point presentation on a preferred topic among those of the course, during which the commission will ask questions to assess the student's degree of learning. The written exam, if required, consists of an open-question test on the topics of the course; the practical test, if required, in a computer elaboration of some of the topics addressed during the exercises.

The oral exam consists of an interview with the examining commission, during which the candidate will have to present the knowledge acquired on two / three topics of the course. During the examination, the commission may ask to the student to clarify what he/she is presenting to clarify any inaccuracies or better explain the topic he/she is dealing with.

Verification of learning can also be carried out on-line, if necessary.

The questions concern the whole course and are aimed at verifying the understanding that the student has acquired on:

- Concepts of Solid Earth Geophysics to define the structure and dynamics of the Earth's interior.

- Geophysical methods of the Solid Earth to define the global model of plate tectonics.

- Application of Solid Earth Geophysics for the understanding of geodynamics, for the definition of seismotectonic and seismogenic models. Analysis of the effects of earthquakes; study of tsunamis, and paleoseismological methods for the assessment of seismic hazard and for the mitigation of derived risks.

Examples

What kind of variations can earth's rotation undergo and what are they due? What information on the structure and dynamics of the Earth can they give us?

What is the phenomenon of dispersion of surface waves? How does it allow us to define the low velocity layer in the mantle?

Rheological characteristics of the lithosphere

Rheological characteristics of the mantle

Methods for calculating the density inside the Earth

Geothermal curves within the earth; concept of geothermal gradient, heat flow

Behavior of materials subjected to stresses

Equation of the gravitational potential

Equation of magnetic potential

Methods of paleomagnetism

Free oscillations of the earth; what they are and what information they give us about the interior of the earth

Definition of seismic hazard and seismic risk

What are seismites and paleosismites

How is a paleoearthquake dated in a trench?

Tsunami, where they are distributed, causes and propagation of the waves

Definitions of active fault, seismogenic fault, capable fault