EXPLORATIONAL GEOPHYSICS AND ENVIRONMENTAL GEOPHYSICS

Module EXPLORATION GEOPHYSICS

Learning outcomes of the course, outlined according to the Dublin Descriptors.

A. Knowledge and understanding.

The student will learn the fundamental principles of applied geophysics, with particular attention to the methodologies used in various geological contexts. Techniques such as seismic reflection, seismic tomography, borehole seismics, and marine seismic exploration techniques will be explored, including the fields of applicability and limitations of each methodology. The student will acquire skills in the analysis of surface waves (MASW, ReMi, HVSR) and in the use of Ground Penetrating Radar (GPR), understanding how these methodologies are used for the geophysical characterization of the subsurface and the identification of geological layers and mechanical properties of soils.

B. Applying knowledge and understanding.

The student will be able to apply the acquired knowledge to the characterization of the subsurface and the evaluation of geophysical properties in a variety of contexts, including urban and marine environments. They will be capable of conducting field investigations using geophysical methodologies appropriate to the specific context, processing the collected data, and interpreting it for subsurface modeling.

C. Making judgements.

The student will be encouraged to independently deepen their understanding of the topics covered and to prepare reports on the techniques used and the procedures for geophysical data analysis. Through involvement in practical scenarios, the student will be motivated to develop an independent approach in evaluating the most suitable geophysical methodologies for specific contexts. Additionally, critical discussions with peers and the instructor will be encouraged, allowing the student to monitor their learning process.

D. Communication skills.

Active participation in lessons, the study of didactic material, and the drafting of technical-scientific reports will allow the student to develop the ability to express and argue clearly and precisely, both in writing and orally, regarding the methodologies adopted, the analysis procedures, and the results of geophysical investigations. The student will be able to use precise technical and scientific language appropriate to the field of applied geophysics.

E. Learning skills. 

Through practical activities and the drafting of technical-scientific reports, the student will be guided in improving their study method. They will be able to independently tackle new topics related to geophysics in urban areas, identifying the prerequisites necessary to understand new tools and advanced geophysical analysis techniques.

35 hours (5 credits) of lectures, 12 hours (1 credits) of laboratory.

Information for students with disabilities and/or Specific Learning Disorders (SLDs)

In order to ensure equal opportunities and in compliance with current laws, interested students can request a personal meeting to plan any compensatory and/or exemption measures, based on the educational objectives and specific needs.

It is also possible to contact the CInAP (Center for Active and Participatory Integration - Services for Disabilities and/or SLDs) reference professor of our Department, Prof. Giorgio De Guidi.

Introduction - Introduction to geophysical methodologies applicable in urban, rural, and marine environments, including the design of a geophysical acquisition campaign: fields of applicability, limitations, and potential of the main geophysical methodologies discussed.

Reflection Seismics - Basic principles of seismic waves, theory, and instrumentation. Survey, geometries, and acquisition configurations. Data processing: travel time curves of reflected waves; normal moveout; RMS velocity; filtering; horizontal-vertical resolution; deconvolution; stacking; migration; interpretation. Applicability in urban, rural, and marine environments.

Seismic Tomography - Basic principles and theory. Instrumentation and survey, geometries, and acquisition configurations. Data processing.

Borehole Seismics - Cross-hole test; Down-hole test; Up-hole test; fields of applicability.

Marine Seismic Exploration Techniques - Deep seismic with high-resolution single-channel sources (Sparker) and high-penetration multichannel sources (Air Gun); very high-frequency acoustic methods (Side Scan Sonar and Multibeam) and high-frequency methods (Sub-Bottom Chirp).

Active and Passive Seismic Techniques for Surface Wave Analysis - Theory of surface waves; Masw technique; Refraction Microtremor Analysis (ReMi); Nakamura technique and spectral ratios (HVSR); case studies.

Ground Penetrating Radar: GPR method; theory and applications with particular reference to engineering, archaeology, cultural heritage, and forensics.

Overview of Seismic Hazard and Risk - Deterministic and Probabilistic methods for seismic hazard assessment. Basic seismic hazard. Local seismic hazard.

Local Seismic Response and Seismic Microzonation - Seismic amplification; Nakamura technique and spectral ratios (HVSR); case studies. Seismic microzonation; local geology and assessment of soil conditions; site effects; effects due to heterogeneities, presence of geometric and topographic irregularities, tectonic structures, and cavities.

1.   M. Corrao e G. Coco (2021). Geofisica applicata. Con particolare riferimento alle prospezioni sismiche, elettriche, elettromagnetiche e geotermiche. Flaccovio Dario editore.

2.    J.M. Reynolds (2011). An Introduction to Applied and Environmental Geophysics (Second Edition). Wiley-Blackwell Editore

 3. Gruppo di Lavoro, Linee guida per le buone pratiche dell'analisi delle onde superficiali, 135 pp. CNR Edizioni, 2021.

4. Gruppo di lavoro MS, 2008. Indirizzi e criteri per la microzonazione sismica. Conferenza delle Regioni e delle Province autonome - Dipartimento della protezione civile, Roma, 3 vol. e Dvd.

What are the similarities and differences between seismic exploration methods?

Illustrate the Nakamura Technique or spectral ratios (HVSR).

Illustrate the main steps of data processing in a seismic reflection survey.

Illustrate the main exploration techniques in the marine environment, differentiating them in terms of effectiveness and applicability.

Describe borehole seismic techniques.

What is the difference between active and passive seismic? What are the main strengths and weaknesses of the various active and passive seismic techniques?

What does the maximum depth that can be investigated with a geophysical profile depend on?

What is Ground Penetrating Radar? What are the fields of applicability?

Illustrate what the MASW and ReMi techniques consist of