Advantages and Disadvantages of Seismic Methods
When compared to the other geophysical methods we've described thus far, the seismic methods have several distinct advantages and several distinct disadvantages.
Seismic Methods | |
---|---|
Advantage | Disadvantage |
Can detect both lateral and depth variations in a physically relevant parameter: seismic velocity. | Amount of data collected in a survey can rapidly become overwhelming. |
Can produce detailed images of structural features present in the subsurface. | Data is expensive to acquire and the logistics of data acquisition are more intense than other geophysical methods. |
Can be used to delineate stratigraphic and, in some instances, depositional features. | Data reduction and processing can be time consuming, require sophisticated computer hardware, and demand considerable expertise. |
Response to seismic wave propagation is dependent on rock density and a variety of physical (elastic) constants. Thus, any mechanism for changing these constants (porosity changes, permeability changes, compaction, etc.) can, in principle, be delineated via the seismic methods. | Equipment for the acquisition of seismic observations is, in general, more expensive than equipment required for the other geophysical surveys considered in this set of notes. |
Direct detection of hydrocarbons, in some instances, is possible. | Direct detection of common contaminants present at levels commonly seen in hazardous waste spills is not possible. |
If an investigator has deemed that the target of interest will produce a measurable seismic anomaly, you can see from the above list that the primary disadvantages to employing seismic methods over other methods are economically driven. The seismic methods are simply more expensive to undertake than other geophysical methods. Seismic can produce remarkable images of the subsurface, but this comes at a relatively high economic cost. Thus, when selecting the appropriate geophysical survey, one must determine whether the possibly increased resolution of the survey is justified in terms of the cost of conducting and interpreting observations from the survey.
Seismology
- Simple Earth Model: Low-Velocity Layer Over a Halfspacepg 11
- Head Wavespg 12
- Records of Ground Motionpg 13
- Travel-time Curves for a Simple Earth Modelpg 14
- First Arrivalspg 15
- Determining Earth Structure from Travel Timespg 16
- Derivation of Travel Time Equationspg 17
- High-Velocity Layer Over a Halfspace: Reprisepg 18
- Picking Times of Arrivalspg 25
- Wave Propagation with Multiple Horizontal Layerspg 26
- Travel Time Curves from Multiple Horizontalpg 27
- Hidden Layerspg 28
- Head Waves from a Dipping Layer: Shooting Down Dippg 29
- Head Waves from a Dipping Layer: Shooting Up Dippg 30
- A Field Procedure for Recognizing Dipping Bedspg 31
- Estimating Dips and Depths from Travelpg 32