R. M. Russo
Assistant Professor
223 Williamson Hall
+1 352 392-6766
rrusso@ufl.edu
Office hours
MWF: 11:40-12:40
or by appointment
NSF Chautauqua Short Course on Seismic Imaging
July 16-18 2006:
Redacted versions of the powerpoint presentations of the Short Course
are available for download here. Copyrighted material shown
during the course has been deleted. Images I downloaded from the
web are of uncertain copyright status - proceed with caution! All
other images Copyright R.
M. Russo 2006, but may be freely used by educators for their teaching.
Part I powerpoint
Part II powerpoint
Part III powerpoint
Part IV powerpoint
Course Texts:
Understanding
Earth, 5th Ed., by Grotzinger, Jordan, Press, and
Siever
An
Introduction to Seismology, Earhquakes, and Earth Structure, by S. Stein & M. Wysession
Course Outline:
Day 1
Introduction and Overview
0. The Goals:
i. Earth structure,
from local to global scale
ii. Earth dynamics
iii. Earth's evolution
A. The observables:
i. Arrival times of
seismic waves
ii. Waveforms
B. Sources of Seismic Energy:
i. Artificial events -
explosions and shaking devices
ii. Earthquakes
iii. Landslides and
submarine slumps
C. Indirect approach to Earth structure:
i. Mean density of the
Earth vs. observed surface densities
ii. Moment of inertia about
the spin axis
iii. Infer there is a dense core
iv. Use seismic waves to see
more and better
Part I: Imaging Near Surface Structures - Crust and Uppermost
Mantle
A. Refraction of Seismic Waves
i. Methods of active
source refraction studies
- How to proceed when origin time is known
- Often assume flat, layered Earth
- Review of Huygens' principle
- Fermat's principle, travel times, and ray paths
- Review of Snell's Law and ray path concept
- Waves propagate within layers
- Waves also reflect off layer boundaries
- Waves refract along layer boundaries
- Travel times relate directly to layer velocities
- Direct wave-refracted wave cross over yields layer thickness
- Multiple layers and iterative structural calculations
- More complicated structures
- Structure on continental scale
- What seismic velocities can tell us about mineralogy at depth
Day 2
B. Reflection of Seismic Waves
i. Methods of active
source reflection studies
- How to proceed when origin time is known
- Reflected wave travel times
- Reflected wave amplitudes and waveforms
- Detailed crustal structure
ii. Methods using earthquakes
- How to proceed when travel time is not known
- Receiver functions: seismic wave conversions
- Structural inversions for crustal and upper mantle velocities
Part II: Imaging the Earth's Deep Structure
i. From flat Earth to
spherical
- Ray paths, Snell's Law
- Radial Earth models: example Herglotz-Wiechert
- Composition of the mantle and core
ii. How to locate earthquakes
- Travel time inversions for lat, lon, depth, origin time
- Global distribution of earthquakes, tectonics, and Earth
dynamics
iii. One step further: Using
large data sets to determine structure
- Travel time tomography
- Global Earth structure in 2 or 3 dimensions
- Seismic velocity structure and Earth dynamics
Day 3
Part III: Secondary Observables of the Seismic Wave Field
i. Seismic anisotropy
- In minerals, olivine
- In rocks
- Affect on P waves
- Affect on S waves
- Relationships between anisotropy and deformation
- Observations in the ocean basins
- Observations on continents
- Upper mantle flow at hotspots
- Upper mantle flow at subduction zones
ii. Seismic attenuation
- Scattering and intrinsic attenuation
- Affect on frequency content of seismic waves
- Global observations of attenuation and implications
- Regional observations of attenuation
Conclusions and Discussion
