GEOL 335

## What you are expected to
know (for the exams):

## Seismic methods

- Characteristics of P, S, and Rayleigh
waves
- Requirements to a seismic source
- Sampling interval, Nyquist frequency
- Dynamic range
- Fourier and Z-transforms (descriptive)
- Convolution, cross- and autocorrelation
(descriptive)
- Application
- Relation to Fourier and Z-transforms

- Attenuation of seismic waves

### Refraction methods

- Snell's law, critical refraction, head
waves
- Travel-time and wavefront diagrams
- Critical distance, cross-over distance
- Travel-time calculation in a 2-layer Earth
(horizontal interfaces)
- Intercept time, delay time, reciprocal
time
- Apparent velocity and its application
- Quantitative description of plus/minus
technique
- Generalized
Reciprocal Method
- Elevation and weathering corrections for
shot and receiver locations
- Refraction
statics

### Reflection method

- Physical basis of reflection method
- Wavelets (dominant periods and
frequencies)
- Reflection and transmission
- Reflectivity series
- Convolutional model (seismic trace as a convolution between
the Earth’s response and source wavelet)

- Z- and Fourier transforms (descriptions)
- Acoustic impedance, acoustic impedance
contrast
- Fresnel zone, horizontal and vertical
resolution
- Multiples
- Calculation of reflection time from a
single horizontal interface
- Velocities: apparent, instantaneous
(local),
interval, average, root mean square (RMS), stacking
- Use of RMS velocity, time-average equation
- Moveout time, normal moveout calculation,
NMO correction
- Shot gathers, inner and outer traces,
receiver gathers
- CMP binning and gathers, CMP fold
- Ground roll and its suppression in the
field and during processing
- Airwave and its suppression
- Dipping layer case (descriptive)
- Processing overview
- Migration - plane reflector and point
diffractor cases

### Ground Penetrating Radar

- Factors
controlling wave velocity (dielectric
constant)
- Principles of GPR
- Similarities and differences from seismics
- CMP survey, NMO calculations

### Expressions and diagrams: (also see
this formula sheet)

- Apparent velocity
- Delay
and intercept time
- Stacking
velocity
- Strain and stress
- Hooke's law
- Mohr's
circle
- Elastic constants
- P and S wave velocities
- Nyquist frequency
- Decibels and dynamic range
- Snell's law
- Critical angle
- Apparent, interval, and RMS velocities
- Acoustic impedance
- Normal moveout correction
- CMP bin width and fold
- Basics
of error analysis