Seismology and Data Processing

This module introduces the fundamentals of seismology. It focuses on the initiation of earthquakes, wave propagation, and the analysis of seismic records to characterize an earthquake (location, magnitude, focal mechanism) and image the Earth’s interior. We will also discuss the estimation of seismic hazard. Finally, we will examine how this information allows us to better understand geodynamics and the seismic cycle. The second part of the course focuses specifically on seismogram processing, including an introduction to signal processing techniques during computer lab sessions (Fourier transform, filtering, convolution, correlation) and imaging/tomography. A tutorial using real-world data concludes the year with data analysis, magnitude calculations, and the location and mechanism of earthquake hypocenters to characterize and quantify active deformation in the East African Rift.  

Hourly volumes:

• CM: 25 hours
• TD: 12:00 p.m.
• Practical training: 8 hours

By the end of the module, students will be able to:

• To understand the relationship between stress, strain, and the seismic cycle
• To understand why and how seismology allows us to image the Earth's interior
• To characterize an earthquake (location, magnitude, focal mechanism)

They also have a solid grasp of the fundamentals of seismic data processing and seismic hazard assessment.

• Mathematics concepts: trigonometry, vectors, equations (Grades 1 and 2), differentiation, integration, the concept of gradient
• Physics Concepts: Force Balance, Work, Force, Energy, Conservation Equation

Recommended prerequisites:

• Basic Concepts in Geosciences: Plate Tectonics, Major Interfaces of the Earth's Structure

• Concepts in continuum mechanics and wave physics (period, frequency)
• Concepts of Partial Derivatives and Partial Differential Equations

Ongoing Assessment

Brief description of the concepts covered in fourth grade:

• Concepts of stress, strain, Hooke’s law, modulus of elasticity, and Poisson’s ratio. Strain regimes up to failure: connection to the seismic cycle, types of deformation observable at the surface (folds, faults), and rheological behavior with depth
• Wave Propagation (Equation, Phenomena at Interfaces, Hodochrones)
• Location and magnitude of an earthquake; focal mechanism
• Seismic tomography and its relationship to physical parameters (temperature, pressure, lithology, fluids)
• Introduction to Deterministic and Probabilistic Seismic Risk
• Introduction to Paleoseismology
• • Major Earthquakes and Tsunamis
  • Introduction to Signal Processing (Fourier Transform, Filters, Correlation, Convolution)

Summary description of the tutorial sessions and the number of hours associated with each session

• Concepts of stress, strain, Hooke’s law, modulus of elasticity, and Poisson’s ratio. Strain regimes up to failure: connection to the seismic cycle, types of deformation observable at the surface (folds, faults), and rheological behavior with depth (3 hours)
• Wave Propagation Equation (1.5 hours)
• Location and Magnitude of an Earthquake, Focal Mechanism (3 hours)
• Seismic Tomography and Its Relationship to Physical Parameters (Temperature, Pressure, Lithology, Fluids) (1.5 hours)
• Introduction to Deterministic and Probabilistic Seismic Risk (3 hours)

Summary description of the lab sessions and the number of hours associated with each session

• Fourier transform and filtering of simple signals (sums of sine or cosine waves) and then of real-world data

• Understand Hooke's law and be able to relate stress, strain, the modulus of elasticity, and Poisson's ratio.
• Understand the ranges of deformation leading up to rupture: establish the connection between the seismic cycle, the types of deformation observable at the surface (folds, faults), and rheological behavior with depth
• Calculate the magnitude of an earthquake, estimate its location and focal mechanism
• Understand how a seismic tomography image is obtained and be able to interpret it (lithology, temperature, fluids)
• Estimating seismic risk in a simple case