84514 - PROSPEZIONE GEOFISICA DELLE AREE SOMMERSE

Course Unit Page

Academic Year 2018/2019

Learning outcomes

At the end of the course, the student develops the basic knowledge for the acquisition and interpretation of geophysical data (morphobatimetry, reflection seismics, potential methods) in a submerged environment, in particular for ultrasound and seismic techniques. As for reflection seismics, problems of interpretation in stratigraphic and structural key will be addressed, using "open" software tools that integrate processing algorithms and data georeferencing. Particular attention is devoted to understanding the interpretative limit of data and the development of a critical capacity for analysis of artifacts based on sound knowledge of acquisition and processing techniques. The great potential of these methods is highlighted in both research and industry, with the presentation of several case studies.

Course contents

The seismic method: historical notes; a brief summary of the theory of the method, with particular reference to the potential in the geological field (basic research, risks, resources, spatial planning, technical geology, etc.); limits and applicability to different geological and environmental contexts; horizontal and vertical resolution of seismic images; attenuation of the seismic signal in depth.
Acquisition of seismic data in submerged areas: acquisition techniques and tools; seismic sources and receivers and their use in different contexts; single and multi-channel configurations; numeric representation of the signal; relationship between frequency content of the seismic signal, penetration and resolution; recognition of artifacts.
Reflection seismic profiles processing techniques: data preparation and decoding; main processing algorithms (stacking, deconvolution, migration, etc.); filtering and return in different formats and representations of seismic sections
Interpretation of reflection seismic profiles: seismic-stratigraphy and geological significance of the reflectors; from "seismic stratigraphy" to "sequential stratigraphy"; reflector terminations and meaning of the internal geometries of the seismic units; acoustic facies of the depositional units and their meaning in analogy to the classical stratigraphy; historical and epistemological discussion on interpretative paradigms and their change over time; interpretation of seismic lines in a structural key; meaning of acoustic stand; meaning of seismic facies; kinematic indicators and synecto- logical deposits; examples of data acquired in different contexts, from continental environments, to proximal or transitional marine, to deep-sea; examples of data acquired in margins with different geodynamic characters (active, passive and transform) and at different spatial scales.
Acquisition and interpretation of ultrasound data: single- and multi-beam sounders, side-scan sonar.
Potential methods (overview): magnetometry and gravimetry.

Readings/Bibliography

AAPG, Memoir 26: Seismic Stratigraphy--Applications to Hydrocarbon Exploration, Edited by Charles E. Payton (1977)

Dal Forno Giulio and Luca Gasperini, 2008. ChirCor: a new tool for generating synthetic chirp-sonar seismograms, Computers & Geosciences, COMPUTERS & GEOSCIENCES Volume: 34 Issue: 2, Pages: 103-114.

Gasperini Luca, 2002. La prospezione sismica in mare. Istituto di Scienze Marine, Rapporto tecnico, Bologna, Giugno 2002 (e aggiornamenti successivi).

Gasperini L., Stanghellini G., SeisPrho: An interactive computer program for processing and interpretation of high-resolution seismic reflection profiles, COMPUTERS & GEOSCIENCES, Volume: 35, Issue: 7, Pages: 1497-1507.

Norinelli A. 1996. Elementi di geofisica applicata. Collana: Scienze della terra Pàtron Ed. EAN: 978885552394. ISBN: 8855523945. Pagine: 312

Wessel, P., W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe, Generic Mapping Tools: Improved Version Released, EOS Trans. AGU, 94(45), p. 409-410, 2013. doi:10.1002/2013EO450001.

Teaching methods

Lectures and exercises with personal PC

Assessment methods

Final oral exam

Teaching tools

Copies of the slides projected during the lessons will be provided as well as non-copyrighted bibliographic material available on the topic used during the lessons. The open software for processing and interpretation of seismic data used during the exercises (GMT, SeisPrho, ChirCor) will be also provided.

Office hours

See the website of Luca Gasperini