69715 - Laboratory of Geophysics 1

Learning outcomes

At the end of the course, students will possess technical and practical know-how on some of the main experimental methods of investigation used in Geophysics.

Particularly, students will be able:

• to understand the operating principles of mechanical and electromagnetic seismometers and to carry out experiments to quantify the fundamental characteristics of an electromagnetic seismometer;
• to read and interpret the fundamental aspects of seismograms and to use them to localize earthquakes;
• to plan, perform and interpret geo-electrical soundings.
  

Course contents

Module 1

• Seismometers and accelerometers. Operating principles. Response curves of mechanical and electromagnetic seismometers. Determination of the natural period, of the critical resistance, of the seismometer constant and of the response curves for the electromagnetic seismometers hosted in the lab.
• Interpretation of seismograms (first arrivals and seismic phases). Hypocenter location through the generalised least squares method: theory and lab tests.

Module 2

• Fundamentals of georesistivity methods. Concept of apparent resistivity. Vertical and horizontal electric soundings. Experiments in the field: planning, acquisition and processing of data from electrical resistivity surveys. Hints on the inverse problem.

Readings/Bibliography

Each lesson is accompanied by the projection of a PowerPoint file. The set of files contains a comprehensive exposition of the program and can act as a text for the study of the subject. The files in PowerPoint and pdf format are available on the Virtuale web site.

If students wish to delve deeper into the topics covered in the course, they may consult the following texts:

Havskov, J. and Alguacil., G. (2016). Instrumentation in Earthquake Seismology, 2nd Ed., Springer.

Havskov, J., Bormann, P., Schweitzer, J. (2011). Seismic source location. https://gfzpublic.gfz-potsdam.de/rest/items/item_43361/component/file_816919/content

Burger, H.R., Sheehan, A.F., Jones, C.H. (2023). Introduction to Applied Geophysics: Exploring the Shallow Subsurface. Cambridge University Press.

Binley, A e Slater, L. (2020). Resistivity and Induced Polarization - Theory and Application to the Near Surface Earth. Cambridge University Press.

Teaching methods

Lectures will be held in the classroom (in presence). Experiments will be carried out in the laboratory and in the field (in presence).

The attendance of the lessons in the classroom is not compulsory, but it is highly recommended for the learning process and for its tight connection to the lab experiences.

The laboratory experiments are compulsory: the lecturers will collect the students' signatures at the beginning of each turn.

 

 

As concerns the teaching methods of this course unit, all students must attend in advance

- Module 1, 2 of the formation course on health and safety (to be attended online)

- Module 3 in presence, based on a schedule that will be timely announced by the Department of Physics and Astronomy.

For further information, please consult the web site: https://site.unibo.it/tutela-promozione-salute-sicurezza/it/corsi-di-formazione/formazione-obbligatoria-su-sicurezza-e-salute-per-svolgimento-di-tirocinio-tesi-laboratorio

Assessment methods

Students, possibly organised in groups, will be asked to prepare three different written reports on the lab experiences connected respectively to seismometry, earthquake location and georesistivity.

The three reports must be sent to the teacher in pdf format within 15 days after the end of the course and anyway before taking the final exam.

The discussion of the reports are part of the final exam, which can also foresee questions on the theoretical aspects connected to the lab experiences.

The final exam is oral and the typical duration is approximately one hour.

Teaching tools

In the room: projector.

In the lab:

· two PCs with free and commercial software for data modelling and visualization;

· two vertical, long period electromagnetic seismometers;

· data acquisition hardware.

In the field:

- georesistivity meter with accessories.

 

Students with DSA or temporary or permanent disabilities: it is recommended to contact the responsible University office in good time (https://site.unibo.it/studenti-con-disabilita-e-dsa/it): it will be their responsibility to propose any adaptations to the students concerned, which must however be submitted, 15 days in advance, to the approval of the teacher, who will evaluate the opportunity also in relation to the educational objectives of the course.

Office hours

See the website of Alberto Armigliato