SAGE 2010 – REU LECTURE – APPLICATIONS OF GEOPHYSICS
APPLICATIONS OF GEOPHYSICS
TO GEOLOGICAL PROBLEMS
A GUIDE TO GEOPHYSICAL MODELING
A) INTRODUCTION:
a. WHAT IS GEOPHYSICAL MODELING?
b. FORWARD MODELING
i. Assign physical parameter as a function of x,y,z.
ii. Compute the results.
iii. Compare it to known data set.
c. INVERSE MODELING
i. Take a known data set.
ii. Assign a physical parameter.
iii. Calculate the distribution in (x,y,z) space
B) HOW TO START – ASK QUESTIONS:
a. DEFINE SCALE OF THE PROBLEM
b. GEOLOGY
c. THINK IN TERMS OF THE ITYS
i. What are the physical parameter(s) that effect the model and how
well are they known?
ii. How good is the measured data set?
iii. How accurate does my model need to be?
iv. Is the data set good enough?
C) HOW TO CONTINUE:
a. WORK FROM SIMPLISTIC TO COMPLEX.
i. If simplistic inverse techniques are applicable – try them first.
b. WORK FROM THE BEST DEFINED LESS AMBIGUOUS TOWARD
THE POORLY DEFINED MORE AMBIGUOUS.
c. WORK FROM LOW RESOLUTION TO HIGH RESOLUTION.
d. ARE MODELS DEPENDENT OR INDEPENDENT?
i. How do the physical parameters interact with each other?
D) HOW TO FINISH:
a. HOW COMPLEX SHOULD I MAKE MY MODELS?
i. Depends on the quality of the data sets.
b. HOW DO I KNOW IF MY MODEL IS CORRECT?
i. You never know.
c. HOW FAR CAN I TAKE MY INTERPRETATION?
i. Depends on the quality and quantity of data sets, integration of
methods, and complexity of the geology
d. CONSIDER THE ULTIMATE GEOPHYSICAL TOOL?