91608 - Seismic Stratigraphy

Learning outcomes

At the end of the course, the student develops basic knowledge for the interpretation of continuous reflection seismic profiles, with particular emphasis on those acquired in the marine environment. Stratigraphic and structural interpretation issues are addressed using "open software" tools, that integrate data processing and geo-referencing algorithms. Particular attention is devoted to understanding the limits of interpretation using seismic images rather than outcrops in the field, and the development of a critical ability to analyze artifacts based on a robust knowledge of data acquisition and processing methods.

Course contents

The seismic reflection method: Historical facts; Brief summary of the method theory, with particular reference to geological potential (basic research, risks, resources, spatial planning, technical geology, etc.); Limits and applicability to different geological-environmental contexts; Horizontal and vertical resolution of seismic images; Attenuation of the seismic signal and the depth vs resolution tradeoff.

Acquisition of seismic reflection data at sea: Techniques and acquisition tools; Seismic sources and receivers and their use in different contexts; Single and multi-channel configurations; Numerical representation of the signal; Relationships between frequency content of the seismic signal vs penetration and resolution of imaging; Recognition of the artifacts.

Processing techniques: Data decoding and preparation; Main processing algorithms (stacking, deconvolution, migration, etc.); Filtering and representation in different formats of the seismic sections.

Interpretation of seismic reflection data: Stratigraphy and geological significance of reflectors; From "Seismic Stratigraphy” to “Sequence” stratigraphy; Terminations of the reflectors and significance of internal geometries in seismo-stratigraphic units; Acoustic facies of depositional units and their significance, in analogy with classical stratigraphy; Sequences, sequence limits and parasequences, in a context of relative changes in the sea level; Historical and epistemological discussion of interpretative paradigms, and their changes over time; Nature and kinematics of geological structures observed in the seismic refelction profiles; Meaning and use of the "acoustic basement" concept Meaning of seismic facies; Kinematic indicators, sin-tectonic deposits; Examples of data from different geodynamic environments and at different vertical scales (continental shallow transitional to shallow-water to marine); Examples of data collected in different margins (convergent, passive and transform) and at different spatial scales.

Readings/Bibliography

Textbook (in progress) and digital presentations of the lessons availble to the students in digital form.

References

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 n., 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.

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

4 CFU lectures;

2 CFU exercises (laboratory or field)

Assessment methods

Final oral examination, after compilation of a report concerning interpretation of seismic reflection profiles carried out during the course.

Teaching tools

Copies of slides projected during lessons and ALL non-copyrighted bibliographic material available on the subject used during lessons will be provided. All software packages for processing and interpretation of the data used during the exercises (GMT, SeisPrho, ChirCor) will be also made available to the students.

Office hours

See the website of Luca Gasperini