Applied geophysis geology 147789587.ppt

Applied geophysis geology 14778958

1. Applied Geophysics
Geology 147
Lecture 1
Introduction
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2. Applied Geophysics
•Identify Geologic Problem
•Design Survey
•Acquire Field Data
•Data Reduction
•Model Data
•Interpret Model
•Write Report
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3. Tonight
•Greensheet review
•Textbook
•What is Geophysics?
•Applied (Environmental) Geophysics
•Methods
•Selection of proper technique
•Designing a survey

4. What is Geophysics?
•Application of physics to studies of the Earth,
Moon, and other planets
•Includes Earth, Atmosphere, Oceans, Planetary
systems

5. What is Geophysics?
http://seg.org/you-geo/definition.shtml
•The study of the earth by quantitative physical methods
•Often refers to solid-earth geophysics only, thus
excluding portions of other subjects
•Exploration geophysics is the use of seismic, gravity,
magnetic, electrical, electromagnetic, etc., methods
in the search for oil, gas, minerals, water, etc., with
the objective of economic exploitation.

6. Examples of Geophysics
•Pure and Applied Geophysics
•Solid Earth
•Surface Geophysics

7. Applied Geophysics
(economic objectives)
•Exploration Geophysics
•Engineering Geophysics
•Environmental Geophysics
•Groundwater Geophysics
•Archaeo –Geophysics
•Forensics

8. Applications?
http://seg.org/you-geo/definition.shtml
•Approach to earthquake hazards
•Plate tectonics, the study of the interior
structure of the earth
•Human's ability to exploit natural resources
•Engineering
•Environmental
•Hydrological

9. Geophysical Methods
•Respond to physical propertiesof subsurface
media
•Can you name some of these properties?
•Passive vs. active methods
•A very wide range of powerful tools
•Can you name some?

10. Examples of geophysical methods?
•Gravity
http://www.vibra-tech-inc.com/content.asp?ID=magnetics_gravity

11. Examples of geophysical methods?
•Magnetics
http://www.vibra-tech-inc.com/content.asp?ID=magnetics_gravity

12. Examples of geophysical methods?
Seismics
a.Reflection
b.Refraction
c.Surface or borehole

13. Examples of geophysical methods?
Ground Penetrating Radar

14. Examples of geophysical methods?
•Resistivity

15. Geophysical Methods
•Critical to select correct tool(s) for objective –
either alone or part of a larger survey
•Need to understand geologic problem, physical
property to be measured
•If physical principles are misunderstood, then
results may be misinterpreted
•Constraints of Study
–Geological, Physical, Financial, Temporal

16. Engineering EvaluationSeismic ResistivityEM GPR MagneticsGravity Borehole Surveys
Soil/Rock Engineering Properties 1 3 3 - - - -
Excavation Characteristics1 2 3 3 - - 1
Foundation Evaluation 1 3 - 3 - - 1
Utility/Rebar Location - 3 2 1 2 - -
Roadway Evaluation 1 2 2 1 - - -
Electrical Grounding - 1 3 - - - -
Geologic Seismic ResistivityEM GPR MagneticsGravity Borehole Surveys
Depth To Rock 1 2 - 2 - - 1
Faults And Fractures 1 1 2 2 - - 1
Sinkholes and Voids 2 1 2 2 - 3 2
Karst Areas 2 1 2 2 - 3 -
Stratigraphic Mapping & 1 2 3 3 - - -
Hydrogeologic Seismic ResistivityEM GPR MagneticsGravity Borehole Surveys
Water Table Mapping 2 1 - 1 - - 3
Water Well Location 2 1 1 2 - 3 2
Seepage Detection 3 1 2 2 - - -
Aquifer Thickness 2 2 3 3 - - 1
Saltwater Intrusion Mapping- 3 1 - - - 1
Aquiclude Continuity 3 3 2 1 - - -
Environmental Seismic ResistivityEM GPR MagneticsGravity Borehole Surveys
UTS'S/Drums/Utilities - - 1 1 2 - -
Landfills and Buried Debris3 3 1 2 2 - -
Soil Groundwater Contamination- 2 1 2 3 - 2
Plume Delineation - 2 1 2 - - 3
Free Product Detection - - 1 1 - - -
Mine Planning Seismic ResistivityEM GPR MagneticsGravity Borehole Surveys
Overburden Estimation 1 2 - - - - -
Sand and Gravel Deposits 2 1 2 2 - - 2
Clay Layer Mapping 3 2 1 1 - - 2

17. Geophysical Methods
•May not yield complete answer or unique
solution; Non-uniqueness of forward modeling
•Many solutions, but which ones are nonsense,
which are plausible
•Interpret within physical constraints &
geological framework

18. Geophysics and Geology
•Geology places
constraints on
geophysical models
•Geophysics places
constraints on geologic
interpretations

19. Planning a Survey -Spatial Aliasing

20. Two and Three Dimensions
Location of Profiles

21. Survey Noise

22. Data Processing -Elimination of Noise

23. Displaying Data

24. Displaying Data

25. Summary
•Course requirements
•Textbook
•Geophysics
•Applied (Environmental) Geophysics
•Gravity, Magnetic, Seismic, GPR & Resistivity
•Selection of proper technique
•Designing a survey